I think Wordpad is altering the file. If I compare the two files in a text editor (like Notepad+), there is a distinct difference. If I simply rename the original file from "lid_6114321769534849026.wfcont" to "test_cache.prt" it opens just fine.
Ron Thellen over at the PTCUser site created a utility to do this for you. It works very well. I have attached both the 32 bit and 64 bit versions to this message. Hope this helps.
