Cannot decrypt a file - error occurred applying attributes to file

I have no idea how, but a file named oem77.CAT C:\WINDOWS\system32\CatRoot\ became encrypted (shows green in explorer). I am unable to decrypt it however, as when I attempt to the following error is produced:

"error occurred applying attributes to the file"

I have tried giving all users all permissions to it, but it seems to make no difference. It also does not appear to be locked by any process (according to the "unlocker" utility.

the os being used is windows xp sp2.

Any ideas?

[etei2nity]

i have an encryted-file decryptor here... i bought it for $199... it works though.. It decrypted my files like in your case and got it just like before(I installed new OS and backed it up, forgetting it was encrypted(green-colored).. it doesn't require any passwords or certificates, and easy to use. I can give it to you for 50 bucks - full version.