ABC keeps stalling out

Since installing Comodo, I’ve been having trouble with ABC (a BitTorrent client). It’s basically working, so this is different from the other Torrent problems I was able to find via Search. Basically, at seemingly random intervals, ABC stops downloading and uploading; at such times, the Task Manager shows it using 90+% of my CPU cycles. Stopping and restarting a torrent usually gets it working again, but sometimes only for a few minutes or even seconds at a time.

I have its port opened in Comodo and have set the stealth ports wizard to “Alert me to incoming connections”, so as far as I can see my settings are the recommended ones for using such a program. However, I just noticed that whenever I open the stealth ports wizard, the radio button is always on “define a new trusted network”, so maybe the settings aren’t taking?

I realize this sounds like a problem with ABC and not Comodo, and I have posted on ABC’s support forum, such as it is. But the problem only started with installing Comodo so I’m wondering if anyone here has any ideas.

-BUMP-

Anyone got any ideas? The problem seems to have subsided to some extent, but I’m still open to suggestions as to what may have been causing it and what I might be able to do to get rid of it entirely.