Cannot make a diagram with 0 pieces on an 8x8 board!
It probably means that you copy a lot of invisible stuff together with the Diagram definition; the line below the quoted error message makes an attempt to show you what you actually pasted. If I copy-paste directly from your latest comment into the PTA, I also get the error message, and for the pasted text it says:
So there is an enormous amount of HTML garbage prefixed and interleaved with the actual definition, and the PTA chokes on it. What exactly corrupts the Diagram definition might depend on your browser. I made the PTA resistant to the garbage that is added by copying from a FireFox Page Source (but you might have to flush the browser cache to benefit from that?)
Anyway, the safest method is to first paste the Diagram definition into NotePad;this will cleanse it of most invisible stuff. Then you can copy-paste it from there into the PTA.
It probably means that you copy a lot of invisible stuff together with the Diagram definition; the line below the quoted error message makes an attempt to show you what you actually pasted. If I copy-paste directly from your latest comment into the PTA, I also get the error message, and for the pasted text it says:
So there is an enormous amount of HTML garbage prefixed and interleaved with the actual definition, and the PTA chokes on it. What exactly corrupts the Diagram definition might depend on your browser. I made the PTA resistant to the garbage that is added by copying from a FireFox Page Source (but you might have to flush the browser cache to benefit from that?)
Anyway, the safest method is to first paste the Diagram definition into NotePad;this will cleanse it of most invisible stuff. Then you can copy-paste it from there into the PTA.