Oh-no, sounds like PTC may have updated all the CAD files to Creo 2.0. This is the latest version of CAD from PTC and supersedes Pro/ENGINEER Wildfire 5.0. I am doing some research now and will find out if this is the case. Hopefully there is a chance to provide the files in WF5.0 format, otherwise you'll need to upgrade to Creo 2.0.
The upgrade is not a big deal and the software can be requested here:
http://bit.ly/QmMZuV