Can't load .PGM file

Tried to load a program I saved last night but I get this:

This file is internally corrupt and can't be loaded: it's internal type ID does't match its 3-letter name extention.

I can load the .SND's OK.

Is there anything I can do to load it?

PGM is corrupt, familiar on floppies, never got this with a zip drive.

Just load the souns,. make the PGM again, save it to a different floppy.