I've searched the string "Nemesis" here on the Elder Scrolls GOG forum and returned no results. I also checked the NexusMods page's posts, bugs, and forums tabs of Nemesis Unlimited Behavior Engine. As of this writing, no solutions have been put forth.

So basically, when I try to run Nemesis Unlimited Behavior Engine from Mod Organizer 2, I can update the engine successfully, but when launching the engine, I get this response:

ERROR(6002): An exception has occured while patching. Report to Nemesis' author immediately
File: _1stperson\idlebehavior.txt
Message: copy_file: The system cannot find the path specified.: "cached_behaviors\SSE\_1stperson\idlebehavior.hkx", "f:\games\steamapps\common\skyrim special edition\data\meshes\actors\character\_1stperson\behaviors\idlebehavior.hkx"

It's looking for the Steam version rather than the GOG version judging by these file paths. I tried starting the Nemesis Unlimited Behavior Engine program in the location of the GOG Skyrim installation, but it didn't even start up. It's my guess this is why some mods, such as True Directional Movement, aren't working. (My dude doesn't have 360 movement. I haven't tried the lock-on functionality yet.)

Try getting on the mod author's github and posting an issue, to let him know. Best advice I have for you, good luck.

Wait, I don't understand.
Are you getting this error even after changing the Skyrim Directory path, or did you not choose the path at all?

You can manually choose the correct path in Nemesis_Engine\nemesis.ini.

Also, by user TheTag on Nexus:

https://www.nexusmods.com/skyrimspecialedition/mods/60033?tab=posts Maybe this can, as TAGma also pointed out, solve the issue.
Good luck.

--edit:

Wait... is TheTag, TAGma?
*forth dimension opens as a plot twist is revealed*

Ah, thank you for your help, everyone!

I'm now facing different error messages. All of them are Error 6002, and they say they cannot find certain files, but all of these files exist in their specified locations. If I run this from MO2, I can see the mods I have enabled. If I don't, I can't see them. If I try to run this program as an administrator, MO2 cannot open it. I'm sure there must be something obvious that I'm missing, but I just can't see it, I'm afraid. The thing is, each time I try to run Nemesis, it gives me an error pertaining to a different file missing.

If I open the Data tab in the right pane, and try to right-click and Execute the Nemesis program, I get an error where it can't find the path "mod\" which is visible in the same pane. If I use "Execute with VFS", I get the same issues as with running it from the executables above.

I, um, hate to be a nuisance, but is it alright to bump a post if you still seek answers for it? I apologize if it's not, but I'd like to hear from other people who may be having difficulties with the Nemesis Unlimited Behavior Engine when using GOG Skyrim. I did change the ini file to find the Skyrim installation folder, but now I'm getting a whole new slew of errors where it tries to find different files in its own installation directory, but somehow cannot. I'm running it through Mod Organizer 2. I admit I'm more than a little stumped, but if anyone can help clear things up for me, then I hope this thread can be useful to others out there facing a similar issue.

Just so we're clear. You added Nemesis to MO2's list of executables (the 2 gears icon). You edited the nemesis ini file to point to your skyrim/data directory. Then you select Nemesis from the right-side drop-down, and hit Run?

Honestly, I haven't had any real issues with nemesis. Don't recall ever editing that ini file. MO2's executable settings do have "force load libraries" checked, but I think that's the default. Perhaps you're running animation packages I'm not. Can you run it without anything else installed? You're using version .84-beta?

FWIW, this seems to be the only thing relevant in that ini on my install:
SkyrimDataDirectory=D:\games\Skyrim AE\Skyrim Anniversary Edition\data\

Yes, I have added NUBE (Nemesis Unlimited Behavior Engine) to MO2's executables, and edited the .ini to point to Skyrim's Data directory. I select it in the executable drop-down and click Run. I am on version 0.84-beta. I update the engine before launching.

I suppose it must be the animation packages I'm running, although these worked fine with the Steam version: Precision, Ice Skating Fixed for Real, and True Directional Movement - Procedural Leaning and Headtracking.

Yet the fact the error message says it can't find files in the NUBE tool's folder which I can find throws me off. I bet it's something silly I've set wrong that's the root of the issue. Hopefully I can find it so I can warn other users who might fall into this same trap.

I wish I had experience with this, but it was such a pain in the butt trying to get everything to work correctly in GOG's version that I refunded it since I already own it on steam.

The mod author probably needs to patch it to make it fully compatible with this version.

I already had TDM installed, so I dl'd the other 2 and didn't have any issue with them in Nemesis with or without enabling their checkboxes (admittedly without any TK Dodge-related things and with some other things along with gender specific animations checked, so it perhaps isn't a clean comparison). Haven't tested the new ones in-game.

You say it says it can't access those files, yet you can see them, so it doesn't sound like file permissions. Nor a missing file issue. It sounds like something is preventing access to those files. If you can see them in MO2's virtual explorer, it's less likely directly MO2's vfs.

Based on my experience using it, leaving out running on something... exotic... like proton/wine on linux or virtual machines, that only really leaves me with either something like virus protection software or the system is running out of file handles to open things. Reading a bunch of files at once / spawning a bunch of threads/processes to do something can sometimes trigger a virus detection response. (I think FNIS suffered from this.)

For the former, you could try whitelisting the MO2/Nemesis directory, or just plain disabling it for a time while you're running Nemesis. For the latter, you could try restarting your computer if you haven't done it in a while.

Only other thing I can think of is to make sure your drive isn't full / near full.

Apologies for my ignorance, but when you say "whitelisting", what do you mean, precisely? Thank you for your assistance!

Tell the antivirus software, such as Windows Defender, to ignore that directory during scanning/monitoring.

In Windows Defender's case, if you search for "windows security" in the start menu search bar, it'll pop up the Windows Security app. Open that, then under Virus & threat protection settings, there's a Manage settings link. Click on that, then under Exclusions, select Add or remove exclusions, then add your MO2 or Nemesis directory to exclude it from being scanned. (These instructions may vary from one Windows version to the next, and will certainly depend on whether you use Windows Defender or some other antivirus software.)

I allowed NUBE through Windows Defender, but unfortunately it still didn't work. Did you tell GOG to install Skyrim to a custom location?

Perhaps there's an alternate to NUBE, but it's not Fiores New Idles System. I tried FNIS, but I still wasn't able to get True Directional Movement to work. As a sidebar, it also seems like FISS doesn't work.

I did install to a custom location. I have a separate drive for games, but, for a time, I also had them on the C drive under C:\games. If you've installed it under "program files", there could be permission issues if you don't run things with elevated permissions. I prefer to not elevate permissions if it can be avoided, so I install them in a different directory.

Edit: This may be more MO2-dependent, since MO2 doesn't technically modify anything in the game's directory. Portable versions of MO2 probably shouldn't be in "program files", but standard installs (non-portable version), I believe, store data elsewhere (users/appdata or somesuch).

Anyways, my install is built like so:

D:\games\Skyrim AE\Skyrim Anniversary Edition (game directory)
D:\games\Skyrim AE\tools\MO2 (portable mod organizer)
D:\games\Skyrim AE\tools\MO2\tools (contains SSEEdit, etc. I've added to MO2)

Easy single directory backup, but feel free to organize them however you like.

Just in case, I uninstalled Skyrim and reinstalled it fresh to a directory outside of Program Files, and NUBE still gives me an error when generating behavior.