XCelsius crashing on exit

We have XCelsius (enterprise - fix pack 3.4) running in several environments, including Windows server 2003, Windows 7, and Windows Server 2008 datacenter SP2 (64 bit).

It runs fine in all environments with one annoying exception - in the Windows server 2008 64bit environment, XCelsius crashes whenever we exit the application. The application window closes, but after a few seconds a popup window appears with a message saying that XCelsius has stopped working. It then records the crash in the problem log that you periodically get invited to check on to see if any solutions have been found.

I have a suspicion that it has something to do with it trying to close the background Excel (Excel 2003) process, though I'm not sure how to verify this. We've tried doing a complete reinstall (first FP3, then FP3.4 - they both install cleanly), have tried changing the application settings of both XCelsius and Excel to run in compatibility mode, as well as running it as administrator - but the crash still happens.

I don't see Windows Server 2008 in the list of supported operating systems, although Windows 7 x64 is supported, which I believe is the same kernel as Windows Server 2008. However, I'm wondering if this is what's causing the problem.

Is anyone else experiencing this issue? As mentioned above, we can use it without any issues - it's just an annoyance to get this crash message every time you exit it.