Hello,
It sounds like STAAD.Pro does not recognize .UPT files anymore. Are you sure that .UPT files still exist in the same folder where STAAD.Pro model is saved?
Maybe you could upload your STAAD.Pro model along with .UPT files used in that model? If you wish, you can use a Secure File Upload on the right side of the screen for uploading the files.
By the way, what is the exact STAAD.Pro build number which you are using?
Regards,
Modestas