Anyone encountered the following issue with Illustrator CS4?

We have the CS4 Master Suite, running on decent spec machines (Windows 7 64bit machines, 8gb ram)

All the other packages within CS4 are running without issue, however we do seem to have one of those annoyingly intermittent problems which are often so much more difficult to diagnose.

When a student is working in Illustrator and goes to save their work , sometimes Illustrator will crash with a "Exception_Access_Violation" error. This causes the work done to be lost.

The problem is that it doesnt happen all the time to the same machine, doesnt even happen all the time to the same student. They can save x number of times without problem and then it falls over, or it could be the first save of the day and it falls over. It happens regardless of file size, can be a blank sheet with just a black line on it or it can be a heavy imaged sheet of work. The students have ample quota within their documents areas to save the file.

I've never had it crash yet whilst using an admin account so I am guessing that its something restriction/permission related, but am drawing a blank as to why they can sometimes save and sometimes not within the same session, given that they have the usual setups regarding both their documents and drive accesses.

I've dug around a bit on google and the adobe forums and cant seem to find anyone else with an identical problem, so I am assuming its something our end rather than adobes.

Anyone seen anything like that with Illustrator? Or maybe with another package within CS4 which might also apply to Illustrator?