Please go to File > Open User Data Folder, and close down PT4.
In the window that opened go to the Apps folder and delete the folder called "Tm90ZUNhZGR5". This will reset the NoteCaddy app files (not any definitions, only the app itself) so that PT4 will download it again when you next run PT4.
If you still have the problem after that please enable logging (Configure > Options) and restart PT4.
Go to File > Open User Data Folder in the PT4 menu.
In the window that opens go to the Logs folder and
compress all of the files there (not the Archive folder, just the files).
Attach the zipped files here so that we can see what is going on.
Tutorial: Reporting a problem