This is not the actual error, but because the script in "myString" has been called by .doScript, ID cannot display the actual error message.
Can you run the script without using .doScript? It should be possible; this is just a wrapper, to be able to "Undo" the entire called script in one swell foop. Running the script directly will give the actual error message, together with its line number.
Is it possible that the definitions file has gotten saved with a different encoding or line endings than the most recently-working version?
You can send me your text file directly, if you like, and I can try to figure out what's wrong.
I hope I haven't wasted your time - I've just discovered the problem, proving the old adage that 'a little knowledge is a dangerous thing'.
I had set up a template file to use as a basis to run and develop the script. This has all the required paragraph and character styles resident.
I had forgotten this (getting old!), and was trying to use an older document reflowed with new text content to run the script!!!!
Sorry, script runs perfectly on right document!