Pad.7z.001 -

Many split archives (especially from forums) are password-protected. Check the source where you found the link for the key.

The filenames must be identical except for the numbers at the end. PAd.7z.001 , PAd.7z.002 PAd.7z.001

This means one of the parts was corrupted during download. You may need to use a "Repair" tool if a .rev file was provided, or simply re-download. or simply re-download.