I know your product is great... and I'm pretty sure you did it this way for a reason.
however, the question remain:

1. install Oleguids in Syswow64 ? regtlib Oleguids.tlb ??
2. over last version, do we need to uninstall the Oleguids, if so, wich method do you use, RegTlib doesn't have -u
3. do we need manifest, if so, how to implement, where to place the file

as for the on error hack, I got other class that I use that need to use the error debug as it is by default.
so I'm stuck...

and finally... it doesn't explain why the Vb6 IDE completely crash and close upon this error. are you subclassing ? (if so I missed it)