[Serusers] SER hung - Log Information?

Hello list. I had been experimenting some weird behavior in my SER program. A couple of times my SER seems to be hung. For example the first time, all the REGISTER messages reaching the server were not challenged, even worst the server don't respond anything. The second time it happened with the INVITE messages. The weird thing is that the SER process were still running. I don't know what could cause this problem, but my question is : Is there a way to log information about the "internal system process" to have a clue about what is happening?. I would really appreciate any help. Thanks Ricardo Martinez.-