[Serusers] SEMS stops taking audio with a particular ATA

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.