Wow.... I have found many things during my check on my TB trades...
1) PR hasn't been updated in 2 years
2) The bot isn't checking trades where both members are free so I am finding tons of my inbound links are there and the page is either down due to not being renewed in months or is a parked domain page.
If you want an active service that handles link trading, use
http://www.linkspun.com