Just sent another log. Since I had auto-import off for the last week or so, I manually ran an import from my NAS' music directories overnight. I did not think about the m4p Apple DRMed files that we'd previously excluded, so I was concerned when the last dialogue box this morning said that the import was successful for something like 879 files. It was only when i saw the newly added files list that I realized what had happened. So, for now the m4p's are back in the library.
Then, from work, I used Splashtop to access my computer remotely. Over this connection, which seems not to impact other apps significantly, MC became unusable. I would type "John Stubblefield," for example, would have the "J" echo and then NOTHING else for seemingly minutes, until the rest of the man's name appeared in the search dialogue box and the correct search results displayed. While I was staring at the "J" sitting there in the search box, the W8 "not responding; what do you want to do?" dialogue appeared twice. So, right now, I'd say that, at least remotely, I can't use the application if there are m4p's in the library.
I have reset the log. Now I will go back and delete those files from the library again. I'll keep you posted.