Hola Alex.
KJV is the traditional version and KJVAM is a modern English adaptation, with subtle modifications in grammar, vocabulary or punctuation.
Did you close and reopen Paratext after downloading the missing resources (such as the NASB)? In the case of changes that affect files, such as adding/updating a new resource, it is necessary to reopen Paratext to “load” these new files. If even reopening fails, it will be faster if you can open them again and save the Layout with the same name.
If you still have access to the other computer you can move your Layout from the “_WindowCollections” folder in “My Paratext # Projects”.
Saludos,
Pepe.