Every time I try to save after loading an older save from the CD version, it crashes and exits to desktop.

Your answer is here
http://www.gog.com/en/forum/divine_divinity_series/remastered_version_vs_cd

Eh that's not really an answer, is it. Well at least it seems like I'm not the only one with such save problems.
Hopefully it will be solved with the patch...

I can't find the post but . . . it is my understanding that the GOG version does not support saves from the retail version. The GOG version has unique changes that the retail version will not work with. I believe if you will ask GOG support . . . they will confirm that retail saves are not supported by the GOG release.
The only reference I could find was this post by DeathKnight, a Larian Dev, who is confirming that the old GOG version saves will work with the new patch. Hope this helps . . .=)

Well let's wait for the patch...

I am still waiting for reply to my email to DeathKnight to finally confirm if my saves from 1.34 retail will work with this patched GOG.com version... :(

You might want to ask GOG support as well. Their response should be quicker and they are most likely to know the correct answer. . . . =)

I think I go begin all over again an New Game hihi ...
And this time I play on "hard" difficulty (or Normal). I never play the whole game to the end on "Normal or Hard" ! Always on "Easy".
I downloaded first of all the soundtracks, great music, love it so much!!
I wonder what I do best: download the game via webbrowser or via GOG-downloader: what's the best way? Is there a big difference between both methods for downloading this game? I'm confused about this.
Thanks in advance

There is no difference in the file that is downloaded. The advantage of the GOG downloader is it can resume a download I believe. I always use my browser and have never had a problem. If you have a slow connection or one that has intermittent fails than you should probably use the downloader.
DD is around 1.6 GB so it will take some time to download.
Enjoy the game . . . =)
Your post in this thread is asking if the CD version saves will work in the GOG version? I don't believe GOG's version supports the CD version. You might want to open a help ticket with GOG support and get them to clarify on that point.

Thanks Stuff !
Now I understand more about the two ways for downloading!
I read already people they having troubles with old saves, so I decided to begin all over again if I'm download and install DD again ... I love this game and the very first beginning of DD :-p

You're welcome. If you are running Vista or Win 7, make sure you right click the down loader setup.exe and click "Run as an administrator" in the resulting dialog.
DD is one of my favorite games as well . . . =)