[_ck_]

It sounds vaguely to me like a timeout issue, where something in the ajax is waiting for a response from the server.

It would probably take more debugging time that it’s worth, you’d have to watch requests in realtime either from your side through a firewall or from the server side logs (ie. tail).

I haven’t kept up with the ajax changes in wordpress since 2.1 so I have no idea what’s going on there – wish I could be more help. Ajax is usually the first thing I gut out of wordpress (and bbpress).