Corruption in a PXE boot image is very rare, however, if it were to happen, the easiest way to resolve the issue would be to:
1. Stop the PXE Config Helper service on the damaged PXE Server.
2. Delete the pxe.ini file from the PXE folder.
3. Delete the menu option folders from the PXE\Images folder.
4. Start the PXE Config Helper service back up.
This will allow the specific PXE Server to download all its boot menu options again from the PXE Manager.