Thanks for your reply.
I created the /forcefsck and rebooted. The file system check started, ran to 100%, said there were errors and asked me for the root password to run manual maintenance. I ran e2fsck on each partition but it said no errors were found. I rebooted but the /forcefsck was still there which started the file system check again. This time it completed without error and the system booted normally (from that point on). When I checked the /forcefsck had been removed.
Unfortunately I'm still sitting with incorrect results. The way I calculate it the system has 86.5% in use, not 90%. Available should be 10107784, not 6668344.
Any other suggestions?
[root@vrod root]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/ida/c0d0p2 67709088 57601304 6668344 90% /