Try running it with admin rights (right-click the file and select the Run as Administrator option)

Did not work, when i run the exe for the first time I get a msg that tells me that I need to run the exe again, but when I try I get the no permission msg, even if I run it as admin.

I tried with other Weimer's BG2 Mods and got the same problem.

Directories can be a problem, or so I've heard. Is your game installed in the Program Files directory? If so, that may explain it. Try re-installing in a different directory.

If that's not the problem, I'm afraid I've got nothing.

Honestly though, you could also decide to skip these mods. Weimer's mods are... eh... some people like them, and the guy deserves all the props for his work on the modding tools that enabled so many other great mods to be made, but I don't care for either his writing or his combat encounters. Way, way over the top. (Well, the writing thing mostly applies to Soulafein, for fairness' sake. I don't recall Valen's writing being bad, but then there's not much story to her.)

The game is on c:gog games/BG2

It is strange, first time it happens, tried with another NPC mod (Amber and Tashia) and it did not work.

The rest of the mods work, it looks like only NPC mod are not working.

There is absolutely no reason why one weidu mod will install and not another, because ALL weidu mods use the same installer (weidu.exe renamed to the mod). My guess is that you have a mod/mods that you are not extracting correctly, or to the correct (BG2) folder path.

I think I found what is happening, files are not downloading/extracting correctly.

I downloaded the wide screen mod and got the exe file and a part file, instead of one file, same when I extract a mod.

Tried a new install and the game is not installing correctly, In the game folder I get exe and part files.

You mentioned you are using Firefox, which uses *.part files as temporary files during download. When a download is completed correctly, the -.part file becomes the intended extenstion, ie. *.zip . This means that your downloads are incomplete, or are being interrupted. My suggestion to you is to use the GOG downloader.

I downloaded them with chrome and the file was good, but after re-installing the game I cannot play it anymore, I get a "the file directory has moved" msg.

I go to the game folder and I see the unins000.exe and unins000.dat, so the game is not installing correctly (I download it with GOG downloader).

This is the only GOG game that is giving me trouble, Wasteland 2 works fine.

It has to be something whit extracting, since when I extract a file I cannot delete the folder for some minutes.

Strange thing is that it is only happening with some BG2 mods.