FreeBSD cpup last night: cpanel error

Running FreeBSD 4.10

Did a cpup last night after getting the apache warning and now users are seeing a message saying that the root partition / is full and cpanel has been disabled. However no partitions are full at all....

Sorry for the inconvenience!
The filesystem mounted at / on this server is running out of disk space. cPanel operation has been temporarily suspended to prevent something bad from happening. Please ask your system admin to remove any files not in use on that partition.

Filesystem 1K-blocks Used Avail Capacity Mounted on
/dev/aacd0s2a 1032142 164802 784770 17% /
/dev/aacd1s1e 69981576 14452998 49930052 22% /home
/dev/aacd0s2e 2064302 12948 1886210 1% /tmp
/dev/aacd0s2g 17628750 2792636 13425814 17% /usr
/dev/aacd0s2f 10080382 1105396 8168556 12% /var
procfs 4 4 0 100% /proc
/dev/da0s1e 241281108 38684366 183294254 17% /backup

This should be an easy fix, but I don't know where to start looking.

jafo