Not surprising. You had to be running Python 2.x somehow, and that was the most likely candidate. The script now avoids the conditional syntax introduced in Python 2.5, so there's no reason it wouldn't work.
I labeled all the relevant pieces for you in this post. Just watch them working at a reasonably slow speed and you'll see the data source switching from the ROM to the PRNG and back again.
And there's no need to "work around the crypto" -- it's not really crypto since there's no encoded message, just a random bitstream -- just disable that part of the mechanism. In the same message there's a version of the telegraph that makes a good starting point, with the PRNG and switching system removed.
The last TODO item here is to adjust the loader script to allow arbitrarily long messages. Jormungant's ROM could easily be extended to fit in 1000-character-plus messages, before the size of the ROM started to compete with the size of the telegraph. Or we could just build the usual square or diamond-shaped box with lots of Snarks, and store the raw glider stream instead -- basically using a larger version of one of the storage loops in this Cordership gun. (We could use the double-spiral design found in the p2^23 loafer gun and elsewhere, but it's been shown that those really drag down Golly's speed compared to a simple back-and-forth packing.)
