Was the vertex count or sequence changed while the new head shape was sculpted ?

Went something wrong while saving the resculpted figure ?

Maybe Poser 7 isn't compatible with the way the modified cr2 was re-safed in PP-2012 ?

Sorry, but the procedure jorca has posted doesn't make any sense to me, and I morphed a lot of figures in the past. Lol.

You morph a figure, you save it as a new figure to your library.

If you want to redistribute the morph you can distribute the whole cr2 (not recommended), make an injection pose (if commercial), or export the morphed object file(s) so that it can be loaded as a morph to another copy of that figure.

That's the easiest and most trouble free way to distribute a simple morph.

Sorry, without having access to that cr2, that's all the advice I can give.

Good luck.