Sometimes if /tmp is not pointed properly on a Linux server, it can cause all sorts of problems and many things stop working altogether. As good as the cPanel /scripts/securetmp script is, it can sometimes break as well.
If you are getting /tmp permission errors, php session erors or yum prescript errors, this will fix it 99% of the time:
umount -l /tmp
umount -l /tmp
/etc/rc3.d/S05securetmp start
chmod 1777 /tmp
If you still have problems open a ticket.
