More information: I plugged the hard drive into a mac and I am able
to access the files. I talked to a co-worker of mine who has the same
issue with a thumb drive.
I defer to the others about recovery software, since I haven't used any
in over 5 years.
Please do *not* do anything that writes to your hard drive until after
you have recovered your files. There is always a risk that something
further will go wrong, especially if you end up trying to recover
deleted files or files that seem to be deleted - the recovery software
must be installed on and run from a different drive, and the recovered
data must be written to a different drive. By "different drive" I mean
something other than the problem drive.
It may be possible, on a Mac, to copy the entire drive to a new drive
that you can read in Windows (i.e., FAT32).
There is also software available online that lets a Windows computer
read a Mac drive. Look here (or Google):
http://ogasawalrus.com/blog/node/208
The link is for HFS Explorer, which I have used; it's free. There are
others, not all free.
I wish you luck - it seems like a real bug in the Mac system, and not
easy to fix.