If you need to increase the size of the /tmp partition, please follow the instructions at:
http://forums.cpanel.net/f5/tmp-wont-increase-size-37085.html
If you look at your /scripts/securetmp script, you will see a line defining $tmpdsksize. Consider changing this as follows to get a 1GB /tmp partition.
my $tmpdsksize = 1048576; # Must be larger than 250000
Hopefully this will eliminate the any full /tmp partion problems.