That didn't help. But let me tell you a bit more about the scenario, symptoms, what I found and how I resolved it.
Scenario and Synptoms:
After creating some new styles affecting nearly every object in the Object Style Manager, I created a new theme and added it to my themes panel. The new theme saved successfully, with not indication of errror. I then relauched C7 and opened an existing project. When I tried to apply a standard theme, it appeared to be working until the end, when it popped a window stateing the new theme could not be added (no indication as to why). When I tried to apply my new custom them C7 crashed immediatly, with no error message at all and not even a message when I relaunched C7 that there had been a problem during the previous runtime.
I followed your directions on Win7 and the problem did not change.
Findings and Resolution:
Suspecting a corrupt or bad theme, I renamed it and relaunched C7. This time when I tried to change to a standard theme, everything worked as expected.
I then created another custom theme like my original (before the extensive style changes) and everything still works as expected.
If I try to apply the suspected theme now, it appears to work the first time, but if I try and changeit the problems start over again as I described above.
Summary:
I suspect the custom theme was somehow corrupted. If Adobe is interested in testing further, perhaps I can send you the corrupted theme. For now, I have a reasonable work-around.
Thank you.