MSN is not working for me (8310 OS 4.2 and/or 4.5) either ..
- why ? - I guess the fact that this is not a Win Mobile 6 platform has something to do with it .. unlike Google talk that works on everything !!! Oh well ..
anyway .. my solution to that was -- pay $20 and get JiveTalk and use that for Google, Live and ICQ at the same time (with only one app running in the background) .. not bad.