I've tried Adium on my new MacBook and for some reason it won't work. I'm on Leopard 10.5.5. Oddly enough Messenger won't work either. I get error messages telling me that my username or password is wrong or that the connection has just timed out. It runs fine on my PC and old Mac. Any ideas anyone...?
I have a new MB with 10.5.5 and I don't have the problem you're experiencing. Did you migrate data to the new MB? Files may have gotten corrupted or something. You could try removing the Adium plist file (com.adiumX.adiumX.plist) from ~/Library/Preferences then restart Adium. I would move it to the Desktop and then just move it back if it doesn't resolve the problem. You might also delete the keychains if the plist idea doesn't prove fruitful.