Hi, here's the result of my examination. The stack size limit set by Gridengine is the culprit. Somehow, the h_vmem limit I gave to my Gridengine job translated into setting the stack size limit to this value (ulimit -s). I've edited /etc/security/limits.conf on all my nodes, adding a hard stack size limit of 10240 and the problem is gone.
Sorry for the noise, regards, Götz Waschk -- AL I:40: Do what thou wilt shall be the whole of the Law.