Hi

I have also encountered the same error (also intermittent) on our machines (also Win7 and v2010.3) but I have found that if I cancel the error message (press escape) and then go back to File > select and run input file and then reselect the input file it will then run. Sometimes the error message will show up a second time, but if I just cancel it again then I'll be able to run the input file.

Cheers
Bethanie