Just to clarify and help out a little here is an email response I received on this matter:

Our releases are patched to the latest working versions.
The 1.34 patch is actually 1.0034A, which is older than our 1.0061A.

Regards,
Natalia
GOG.com Support

Honestly, the way GOG versions their stuff is really confusing at times... even I have a hard time understanding which patch is which version and understanding if it's the latest official patch or not.. sigh -_-

Apparently support misunderstood the question, or didn't realize the music fix is v1.0062A.

Raze, thank you for uploading music fix patch.

after i patched DD with your files, music seems fine (though i am not sure because i dont have retail version, i can listen some new BGMs on field), but day and night cycle became a bit odd too...it suddenly changes from day to night and from night to day. there is no sunrise or sunset.
is this happening only on me?

The dusk/dawn effect can sometimes be lost (or restored) by re-installing the game or when installing a patch (could happen with the disk version, as well).

Open the '..\Divine Divinity\config.lcl' file (in Notepad, or other text editor) and add the line splotchproblem 0 to the end, hit enter (the game expects the last line to be blank) and save. When you start the game and load a save, the dawn/dusk effect should be restored.

thanx for reply :)
i have tried that as you mentioned, but it makes no effect....i have even tried to reinsall DD. but when i applied music fix patch files onto GoG's most updated DD (patched with GoG's one) , it's always dusk/dawn effects gone :(
i aprpeciate music of DD as well as gameplay very much, but i really need dusk/dawn effect too.
humm.....

The full download (setup_divine_divinity_1.0.2.13.exe) is already at version 1.0061A, so does not need GOG's patch (meant to update the 1.005 release) before replacing the files for the music fix. I don't know if skipping that install will help with the dusk/dawn effect, though.

i have solved this matter with switching rendering system from D3D to Software via configtool.exe.
"splotchproblem 0" in config.lcl was also needed too.

now i can enjoy music and dusk/dawn effects both.
thanx for ur support, Raze :)

## i have deleted here.
because i am not sure what it makes dusk/dawn effects possible again, really.
now its working on D3D in widescreen too. save file related?...idk...

I used to have CD version of DD and now I'm thinking of re-buy it.
But as I've seen in many forum (Larian, Steam, GOG), the game is somewhat messed up.
So could some one please summary and confirm all the bug and fix with the current version on GOG.
I've read that version 1.005 of GOG is not based on the 1.004. I'm I right? So does 1.005 have all the bug fix of 1.004 (scorpion, true sight, etc...)
And, (sorry but) does this meant Steam would be a better choice?
Thank you for making me clear.

GoG and Steam are currently at the same version (1.0062A AFAIK). Changes made by official patch 1.33 (1.0033A) for CD release of the game are still not implemented in 1.0062A.

Actually, it was when the patch to fix a serious new bug in 1.004 was released that some of the changes and fixes in the disk version patches were lost. Some of the fixes in the 1.33 disk patch are in the download version, and some are not. The 1.005 version and 1.006 were actually very similar in terms of bug fixes, though as Tarnum said, GOG has the 1.006 version now, to bring it in line with the Steam / anthology releases.

True Shot and the damage portion of Crossbow Expertise remain broken in the download version, and you can not return Finnigan's lockpicks to complete the quest and buy them back (and he is not a decent merchant). Most of the remaining issues are relatively minor, and/or there are other fixes or workarounds if encountered. Scorpions are still overpowered, but would be unlikely to be fixed now even if there was another patch, since they are recommended in so many walkthroughs, etc, as a strategy for defeating tough opponents.

Is there some kind of list how to avoid bugs and their workarounds if encountered? I'm going to start new DD playthrough and it would be good to know.

There is the outdated QUESTBREAKERS AND MAKING DIV LIFE DIFFICULT.

Early Starter Tips (NON-Spoiler Version) contains a couple warnings, but isn't focused on bugs.

Listing Of Technical Fixes

Basically, just make periodic saves and you should be fine. If you do run into any bugs, it would be relatively easy to revert to an earlier save.
For specifics, don't sneak into the castle before entering by invitation and talk to Janus, don't open chests in the Verdistis sewers without saving if you have a low spiritual resistance...