Think we have been round this loop before, can you confirm the version of the 'ASCOM Telescope Driver for TheSkyX' you are using and what options you have ticked? and also which version of the SkyX, should be using the latest daily build 8908 released May 22nd.
I use V 6.0.5391.19493 of the ASCOM driver and have a full 150 point model with Pro Track enabled, center here works fine and syncs back into the model with no issues, I am not the only one doing it this way so know it works ????
The error you are getting is thrown by the ASCOM driver, I am guessing that you have inhibit Sync check box ticked which is why the error is thrown, is that how you have it configured ?
I cant test with my setup due to constant cloud and even if it did clear everything is broken down while I commission my new observatory but I allow sync into the model, it only aligns the model and does not touch the rest of the terms, have you tried it with allowing sync?