Pete, 
  I tried what you suggested and in the PMDG NG, I get a blank cockpit when I move the PMDGoption.dll file out of the \modules folder and start the aircraft with FSUIPC 3.128.   Move the PMDGOption.dll back again, and I get the cockpit back, but autopilot does not work.  I replace the 3.128 with 3.125 and everything works again (as it has since I purchased and registered FSUIPC 3.00).  Seems to be just this release. 
  I also tried to load the Simulation Software Workshop's A310 and I get a message that "wrong or no FSUIPC" is present, the a "Failed to connect to FSUIPC" message.  When I replace 3.128 with 3.125, all works well again.  I haven't been over to the SSW support forum and see what they are saying there, just repeated something I saw in my thread in the PMDG forum at AVSIM.  I also have not tried the 3.128 release with any other "Complex" addon I have so may be affecting more than just these two. 
Steve Park