Error firing vbld_BuildStarting event

[CREvans]

I'm running VBPro 6.7 (yes, I know, it's old), and all of a sudden on one build machine I'm getting the following error whenever running a VBPro script. This shows in the log as soon as I try to run a build.

I have not changed anything on the build machine, and it's been running fine for months. Other build machines are still running fine. I even tried re-installing VBPro, to no success.

Error firing vbld_BuildStarting event: Failed to instantiate script engine 'VBScript': Class not registered
Build ended.

Any ideas/suggestions?