Yes we also face some login problem with New version of messenger 5. One drawback of new ver is that you cannot distinguish whether it's not connecting due to wrong id n passwd or service. Maybe new version requried healthy amount of bandwith.
We have switched back to old version 4.8, & it's working quite fine.
While testing I configured these 2 protocol definitions:
MSN File Transfer Inbound PN: 6891, PT: TCP, Dir.: Inbound Sec. conn.: PR: 6891-6900, PT: TCP, Dir.: Inbound
MSN File Transfer Outbound PN: 6891, PT: TCP, Dir.: Outbound Sec. conn.: PR: 6891-6900, PT: TCP, Dir.: Outbound
as secondary connections under the primary connection 1863, TCP, Outbound (because as you know this primary connection is alway's open while using MSN Messenger so file sending should alway's work) but it didn't. So that was the reason why I made the 2 definitions seperated from each other.
I leave it just this way bacause it works fine for me now. I would like to change it and make it even better but I'm affraid the changes apply only after 6 hours. Is this really true? Do the changes apply after 6 hours? I pressed the update now button at my firewall client but no changes were made..