Error -36 with illustrator OSX

In our company we mostly work with illustrator 9 and OS9. As I am the only user with OSX I noticed an annoying problem, when saving from Illustrator (9,10 and CS) I often get the message error -36 I/O error, the only solution is saving to the desktop and copy it by hand.
I am saving to our NAS server, or to our Windows NT server, both get the same error. The problem only occurs working with Illustrator, not in Indesign, Quark, Photoshop or other programs. I have checked my disk and the server's disk thoroughly, so it is not a hardware problem. When I work under classic (under OSX) I get the exact same error, only in Illustrator. The problem never occurs when I reboot to OS9 and work there... It seems to be a Illustrator/OSX problem. Anyone out there having the same problem? We are nog permanently moving to OSX yet, but there will be a time when we have to, you don't want to know how much it will cost to upgrade all our software here in Holland.

To spill another annoyance; the fact that Illustrator CS cannot downsave text, is a reason not to upgrade.