Thanks Rob and Dennis,
I've not yet tried solving in a live situation, i.e. hooked up to the camera and scope in my observatory at night. I've just been trying to solve images that I've taken over the past year with two different scopes, to confirm that I've got the set up right (or at least close). One configuration is my C14+Optec (F7) focal reducer/field flattener which with the QSI583 gives me an image scale of 0.43. The other is my 4" TSAPO100Q also paired with the QSI583, which gives an image scale of 1.91. What I find strange is that PS2 will solve several images taken with either configuration, but then fail on some others. I even worked through a set of 600sec exposures for the same target and it would solve some of them, then time out with that error message on other subs from the same session. I could not see any significant differences between the images. AstroTortilla and ANSVR solve everytime (well almost anyway).
Probably it's not a huge deal if I can configre PS2 with ANSVR as back up (when I've worked out how to do that), but it is weird and somewhat disconcerting that PS2 will sometimes fail to solve almost identical images to ones that it does solve - that makes absolutely no sense to me....!!
As for speed, yes, PS2 solves in a couple of seconds where AT and ANSVR maybe takes 10-20 seconds, however, I'd rather have a successful solve every time in 20 seconds, than save 10+ seconds when it works, but for it to completely fail other times.... It's not going to be a good start to the day if I wake up and find that a session has paused at 1am, becuase PS2 failed to solve an image after slewing to it or after a meridian flip, etc....
Thanks for the help, I'm confident that I can work through this, plus testing in a live imaging session has to be what really counts