[ILUG] VERY strange happenings -> missing dir, but not missing!

[Donncha O Caoimh]

Very strange.. Our dev server here at work seem to be missing a very
critical directory. Telneting into the box I did an ls of the offending
parent directory and saw that the "missing" directory was missing but I
was already logged into the machine in the "missing" directory and I can
move around and inspect the directories no problem. Even typing pwd
showed I was in the correct directory!
Samba users can't see the dir either.
This is a bog standard RH5.2 server which has been running for months
with only the occasional reboot (Usually when someone kicks the power
lead by accident..)
Uptime is 29 days at present.

I'd really appreciate some comments on this as it seems like quite a
serious problem!

Donncha.
PS. yep.. got backups. *wipes sweat from brow*