There are two other posts here about network errors fro Yahoo Messenger. I also had it but this solved it for me:
"...the Port numbers in the Advanced section are updated with garbage values. Editing them to have the default value (Port: 5050 and Xref Port: 80) worked for me.

-Debjit "
See this
http://talk.maemo.org/showpost.php?p...0&postcount=16