I just spent the past few hours trying to debug why my cron job was failing to run to completion on one of my customer's sites. It was narrowed down to Link Checker.
After further investigation, I found that Link Checker is having a terrible time trying to check any myspace.com pages. I ended up removing all the myspace.com links from the linkchecker_link table and configured Link Checker to not check the link status of URIs containing myspace.com
I don't have time right now to debug this any further, so it's really just a heads up to you guys. At least things are working for me again.
Note that this is just a recent phenomenon. I've had the same version of Link Checker running for some time now and all those myspace.com links have been there since day one.