I have uploaded a new alpha version (same url).
This new version will surely not solve the problem per se, but it now will skip trying to even look at formats that are excluded in the advanced rule section.
Once installed, add a rule as follows:

This should prevent CHS from trying to grab the CF_METAFILEPICT format, that causes excel to freak out. It shouldnt have any other bad side effect since CHS can still see the alternate image file format.