I've been working my way through all the fixes suggested in other posts about the unknown error when trying to save a new Illustrator file (reinstalling, deleting or renaming preference files, unchecking the .pdf compatible checkbox, stopping the acrotray process, etc) with no success. However, I'm seeing an additional problem - I'm unable to open existing .AI files - I get the same "unknown error" message. Any further suggestions that might address this problem as well? I'm on XP professional, and Illustrator has worked fine on this machine for two years until this week. Ugh.
Did you also try to Move the folder?
When it is not something in the Adobe Illustrator CS2 Settings folder, it may be (with tests):
1. Corrupt font(s): you may move all fonts out of the Windows fonts folder (and move them back in);
2. Firewall interference (especially if more than one is running (XP SP2 adds one if activated)): you may turn them off (and on again);
3. Some versions of Acrobat generate many temp files. Too many (64K) causes the problem: you may search and destroy Temp files;
4. Some other inconsistency caused by Adobe Acrobat/Reader: you may try uninstalling and reinstalling (a newer version).
5. Incompatible/old printer definition file for the default printer: you may upgrade the driver, change the default, or set the PostScript driver/PDF to default;
6. Using a US/English version of Illustrator with Windows set to a different language: you may enter Control Panel>Regional and Language Setteings and change to English (and change back).
7. Quicktime/iTunes: uninstall Quicktime and make sure the Quicktime folder is deleted in the Program Files folder; and/or uninstall iTunes.
If neither of these possible solutions work, have you made any (other) changes to the PC between succes and failure? New software loaded?
Thanks so much for taking the time to respond. I've tried or checked most of these without success. I'm going to try to the font fix and then the language fix, and then plan B - rebuild my whole damn laptop, reinstall Illustrator and cross my fingers. Man, what a nasty issue...
After working through all the suggestions I could find on this topic in the forum, I threw my hands up and rebuilt my laptop. CS2 works fine now (knocking on wood).
Ironically, as I was setting up my new system, I ran into a problem with type 1 fonts not installing on the rebuilt system, and this time the fix posted on the forum fixed the issue beautifully (http://forums.adobe.com/thread/395613) You win some, you lose some I guess.