this was pointless - outside of the great log file it created...the trace was only of the nxserver -restart and nothing beyond that so no useful information could be derived. I haven't a clue on which process it would be - I presume that it all starts with an ssh connection...
I find strace very useful, usually. It tells me lot of things. Try to look over for ENOENT and EACCESS.
Another question: did you enabled the key authentication in sshd_conf? If sshd didn't accept the connection with keys that could be a problem. Just an idea...
bye, Ago