There was also an earlier error which is perhaps relevant but I left it out because it wasn't xotcl related:
[27/Jul/2011:15:17:49][19913.3079108288][-main-] Error: pidfile: failed to open pid file '/usr/local/aolserver/log/nspid.nccedudotlrn': 'Permission denied'
This is probably due to access rights but I'm not even sure if it is responsible for the xotcl errors.
Thanks.