Excel Has Encountered an Error and Must Close

[hatman]

Okay. I am stymied. I have an application that I built (and maintain) in XL 2010, and almost all of the 500 users run it on XL 2010. However, several big-screen monitors are running it in XL 2007. This has worked fine for several years, until teh last week or 2. Of the 7 big monitors running 2007, 4 of them aere encountering an unhandled error. I can't get a copy of 2007 to do any developement, and the big monitors can;t have 2010 installed on them. From the investigation I have performed, the macros are not the cause of the error. I added a logging routine that keeps track of various steps as the macros run, and in every case the macros complete execution... and yet at some random time between macro calls, XL will complain that it has enconutered an unhandled error and must close. I don't have any idea where to go next with this. Advice would be helpful.