[Serusers] SER stops responding

[AJ Grinnell]

I am having a strange problem with 0.9.0. At random times, SER will
just stop responding. I run ethereal, and can see INVITEs, REGISTERs
and OPTIONs requests, but SER does not respond to any of them. The
process does not die, and moni tells me that SER is still running,
just no respones. Sometimes SER will recover after a few minutes, most
of the time it doesnt. Any ideas?