All images I received solve now reliable in version 0.9.422 just released. It is only available from here:
http://www.hnsky.org/astap_setup.exe
This was a major overhaul of the solver. I tried several approaches and found one which works well. You can now switch off the option “slow”
I have considered updating the database and remove the global cluster center stars but the problem is wide spread. Now ASTAP ignores detected database quads with dimensions smaller then found in the image. As a bonus, the solving speed looks a little better due to an improved program flow.
Would be nice if users could test this version on some global clusters and if they have an image where it still fails, please share it. Or just report problem solved 
Clear skies, Han