I've realised since I responded earlier that there is another possible reason why things may have changed:
If you have enabled Web Display (WD) autostart in PF3, then the port that is used for the WD Remote Text (RT) interface has probably changed.
The default for a manually started WD is 1009, RT port #2 in PF3; autostart defaults to 1008, RT port #1, which is also used by the RT program.
We will be changing this in the next release of PF3 so that, for consistency, manual and autostart both default to RT port #2.
If this is the case then, in the meantime, the workaround is to change the RT program port by editing the PFEPort entry in remotetext.ini
Apologies if this is your issue; to be honest we weren't expecting anyone to run WD with Remote Text enabled and the RT program at the same time.