I have had the same message happen sporadically with certain reports. It turned out to be a label that would end up dividing by 0. Sometimes it would show *** when dividing by 0, which was fine with me. However, it turned out that other times it would cause that "illegal operation..." message. I changed the code so that it would never divide by 0 and it hasn't happened since. That's my vague shot in the dark for you.
hth,
Marcus.

>If anybody has any info that can help with this, even the vaguest shot in the dark, I would appreciate it!
>
>I have a report -- nothing terribly exotic. When I try to run it, VFP crashes -- "This program has performed an illegal operation and will be shut down."
>
>Here's the weird part: When this happenned yesterday, I determined that the report would work OK without anything in the detail band. I figured something got corrupted somehow, so I went back to an earlier version that worked, and re-did the changes I had made between that and the latest version. (The changes involved only adjusting some references, in the title band, to some form properties -- the report is run from a form -- that had moved to the form set when I changed the single-form to a form set, so I had to change THISFORM.blahblah to THIS.blahblah -- which I would have done originally if I had been thinking -- but other than that the end result was the same, and now the report worked.)
>
>[Running the report directly from command window, after removing all form references from the report, resulted in no different behavior.]
>
>Now today, the same thing is happening (after making a large number of changes to the report) -- VFP is crashing. Now the report works only if, outside of the title band, the report contains nothing but labels. I had to remove the summary band and the contents of the detail band. Additionally, some text appears conditionally in the page header -- when it doesn't appear, it doesn't crash, but when it should, it does.
>
>I tried removing the printer info in the report FRX, but it has no effect.
>
>For the record, I am using: Windows 95
> VFP 5.0 (August 21, 1996)
>
>(Even without any other applications loaded since booting, the result is the same.)