I'm using kernel 2.6.31.6 under Slackware 13 and all was fine until a couple of hours ago when a bunch of files disappeared! I was removing certain files from this directory via command line successfully for a few when all of a sudden I was told whatever files I was trying to remove no longer existed. That prompted me to do a 'ls -al', which showed an empty directory!

These files are located on a ext3 partition, with ext4 specified in fstab, effectively giving me ext4 benefits. Anyone have any suggestions? I've tried r-linux and photorec to attempt and recover the lost files, but neither of those programs see anything that resembled the lost files.

I have double checked /var/log/messages and my command history to make sure I didn't accidentally type rm -rf. How can files just disappear?!

They don't.
Your saying that ls show you a empty directory, is this directory in your /home or may be was mounted and is not being mounted anymore for some reason, if so you would just be reading an empty mountpoint.

The directory itself was not a mount point, but it was a separate partition where I stored all my downloads. I was issuing commands like 'rm -rf libsync*.bz2' and 'rm -rf barry*.bz2' when all of a sudden 'ls -al *.bz2' said there were no files with that extension. There should have been at least one file with that extension!

For the sound of it, either another program was accesing the files concurrently and moved or erased them, OR the mount point was umounted for some odd reason, check the kernel log about this one just in case.

Can you post your /etc/fstab

or you typed for example rm -rf libsync *.bz2 .