I just installed the Sold Edge trial (says Premium in the about screen). I would like to open an existing .par file of someone else, also created in Solid Edge, and I get the error:
"The file you are attempting to acces was last saved in a format that is not compatible with the Solid Edge product you are using."
It's a 45 Day Trial... so it doesn't appear to be the Trial issue.
But if the "other" person's Part was done using a FREE Student Addition, then you may get this error.