I can say anything you want me to say but the honest answer is that the only way you can undelete something accidentally deleted on a Linux or FreeBSD server is to immediately shut down the machine and then make a bit-copy of the entire drive in read-only mode, and then do forensics on the bit-copy of the drive while continuing to run your system on the original drive.
If you're running Linux and the ext3 file system, this page (xs4all.nl) may help you.