I've been getting this error ever since I upgraded to the latest version.
It happens everytime the plugin loads. Also, projects saved with older versions of TX16Wx does not load properly. They throw me this error, and TX16Wx shows up with no loaded samples, just the default settings.
So, the modulation preset is a bad, yet rather old "woops". It complains because your preset file contains an entry with "Amp" as destination. However, "Amp" was deprecated already in 2.2.3, so those files should have failed loading (maybe with out a message?) already then.
However, this should have no impact whatsoever on loading projects or sound data files. Can you send me any project (and associated sound data) that fails loading so I can check it out?