I was in a similar situation a number of years ago - IT guy renamed our server and didn't tell anyone, then tried to "fix" the Flexnet but instead made it unfixable. The only way I could get it fixed was to get a PTC expert involved. Had to do a remote access with the person so they could do some really obscure things to repair the damage.
The core of the problem when I was dealing with it was that the FlexNet installation was damaged to a point where it was no longer removeable. An uninstall would leave behind files that would prevent a "fresh" install from working. I don't remember exactly, but there might have been some lingering registry entries that were pointing to bad things, or something like that.
These days, when I need to update the FlexNet stuff, I make sure to clean the old stuff out completely before attempting to install the new stuff. It's usually a very nervous and sweaty Saturday morning operation.
