[Serusers] SEMS stops taking audio with a particular ATA

[SIP]

This is kind of odd, and should really probably be directed toward the 
SEMS list, but I thought I'd pose it here first to see if anyone had 
seen it.

A particular user keeps calling our SEMS server, and each and every time 
he does, it crashes. It ONLY happens with that one user, and only with 
his Cortelco ATA (an identical model to another we have being used on 
our network with no problems).

We get this in the log:

Jul  9 20:26:32 proxy Sems[17552]: Error: (AmThread.cpp)(start)(83): 
pthread create failed with code 11
Jul  9 20:26:35 proxy Sems[17552]: Error: (AmThread.cpp)(stop)(101): 
pthread_detach failed with code ESRCH: thread could not be found.

And then poof, the SEMS server stops sending audio anymore and has to be 
killed and restarted (it still runs and accepts connections). Any ideas? 
Nothing much comes up on a google search for this error.

N.