First note that if there were any changes at all made to the disk between the time the other program undeleted the file and the time you tried UndeleteOnClick then please read the following on why a file sometimes cannot be undeleted correctly:
If you can still undelete the file using the other undelete program but UndeleteOnClick is still unable to correctly undelete the file then do the following:
Make an image of the disk that contains the deleted file using WinImage (free download here). Without the image of the disk we cannot help you.
The disk image is required so we can undelete the file and see where
the problem is. All disk images wil be treated with total
confidentiality. Disk images can be very large (depending on the size of
the disk), so we will need to make arrangements with you about
retrieving the disk image (see next point).