I've seen this a few times. I suspect that every so often, ProE phones home to make sure that your local license is valid. If it does this while you're not connected to the Internet, it pops the error message. In my cases, this terminates the program right now, without even saving your work, which can be irritating. To get beyond the problem, I connect to the 'net and re-launch the program. This worked for me two or three times last night. Might just be a coincidence, but it's easy enough to try. Oh yes, and save your work frequently, because while it almost always does the check on start-up, it also appears to do it occasionally during your session. One other thing--the most recent time I was dealing with this, I appeared to be connected via wi-fi to the school's network. I could not get the error to resolve, though, until I jacked into the wired connection. Not sure whether there was a problem with the wi-fi, or if ProE somehow requires a wired connection. That seems unlikely, but I'm putting it out there as a possibile vertex.
