MSN user not being shown online

[cruciarius]

First off, I've used Adium since... well, a long time. Used to use it 24/7 on my old iMac G4 running 10.4.11. Had no issues at all.

Currently borrowing my brother's Intel iMac running 10.5.8. Copied all my Adium files over. Seems to be fine, except for 1 problem. One of the contacts aren't showing when they're online. If I switch back to Adium on the older iMac, they show up fine. I've already tried deleting the contact and re-adding them, but it didn't fix the issue.

Suggestions?

Edit:
I use a gmail account with MSN and the user that isn't showing up on my contact list uses a hotmail account.