I too failed to get the origional script to work... But after reading all your posts today about asido, I downloaded asido this afternoon from soundforge and hey! It works!!
The only thing it did that confused me was it made my watermark way smaller, but digging through the examples I found that by default it reduces the watermark to 25%. This reduction can be eliminated by adding:--
and, even neater, a custom scale can be added, for example 66%:-
If you want to watermark images then give asido a try.
, ASIDO_WATERMARK_SCALABLE_ENABLED, 0.66