I'm not sure why your looking for the the QNX DDK, but if you are trying to make your own IPL code, you'll need two pieces of software, Xpress and QNX DDK.
I have tried to find Xpress, so I talked to Insyde software, they said National Semi. controls the download of Xpress rom builder. I sent an email to National Semi, they said I have to talk with Insyde.
Help!! I'm in an endless loop, I can't break out!!
I have not started looking for the QNX DDK yet, if I can't get Xpress then its a moot point!