Unable to open copied parts and assembly files

I am moving my files from one computer to the other.  I copied the files from a computer using Creo Parametric 10 to a computer using Creo Parametric 9.  I am unable to open any of the files, even though the association with Creo seems to be valid.  The files show up as .prt or .asm, as they should and they have the proper icon.  But I can open any of them, even simple beam element .prt files.  

So I'm assuming that there's a reason copied files don't work this way.  Is there something different in the setups between the two machines that I should take a look at?

p.s. I'm assuming this question belongs in System Administration, but I'm not sure.