I got this error whenever I ran sudo apachectl restart starting after a recent upgrade to 10.6.5:
/usr/sbin/apachectl: line 82: ulimit: open files: cannot modify limit: Invalid argument
After this reading this post1, I changed /usr/sbin/apachectl line 64 from this:
ULIMIT_MAX_FILES=”ulimit -S -n `ulimit -H -n`”
to this:
ULIMIT_MAX_FILES=””
References
1. deversus.com