Good Morning Friend!!!!
When I opened the second file Scoth File Mechanism I can opened, but both of them link they are broken, if you can save as .step file. and send me a email, to check again. Maybe when you save don't save, all the components!!
and last question, Currently What catia release are you using? I mean catia release 20, 21, or 23?
Hope my comment help you to clarify this issue.
it depends on what version you use...you can't open a future version!
if you are using for example CATIA V5R20 you can't open models created with CATIA V5R21