When importing older P-Cad files into Altium, users might encounter this error message:
This can be due to the P-Cad file being exported/saved in an older version (before 2006.)
You can use a text editor to open the file to see version information:
There are two options available when encountering this error.
If you still have access to P-CAD with a valid license for P-CAD 2006, you can open the file with that version, then use File ► Save as, and then import the newly saved file into Altium Designer.
(What a resaved P-CAD file will look like when opened in a text editor)
If P-CAD software is not accessible, an alternate approach would be to contact the Altium Service Bureaus. Here's a link: