After getting that error on the pt_comments table again, I went into mysql and tried a
check table pt_comments;
and it found an error, so then I did a
repair table pt_comments;
and it said it repaired it, but another
check table pt_comments;
found the same damn error again. So I shut off the web server (so I wasn’t getting hit with comment spams) and did a backup and restore of the entire mysql database, and the problem seems to be gone. For now. Maybe. We’ll see.