Good to hear your problem seems to be solved. I'm no Linux-man. But a couple of problems seem to have nothing to do with PRS+ but with other glitches, for example file system. Says my gut. But as mentioned, I'm no Linux man and no developer.
Concerning Zork for 950:
I have to admint it is very unlikely that there will be a version for the 950 for a couple of reasons. Two of them:
I do not own a PRS 950. Since this model is in some parts very different from the 650 or 350 it would be a risky 'blind flight' to create Zork for 950. I'm not able to test it. So I'll concentrate on Zork for 350 (which I can test) and 650.
My new 'baby' is a Kindle Paperwhite ;-) which's display is fabulous! Software has it's short commings, but the display... So part of my 'reader-time' flows into the Papewhite.
But I'll not give up my beloved 350. This is a great reader which I use outdoor. The Paperwhite has it's problems there. For example you are not able to swich pages with gloves on. No problem with the user programmable buttons of the PRS-X50 readers with PRS+ on it.