My Dingoo can go up to 420Mhz without any stability issues.
I did think that it might be the overclocking that's causing the freeze. Would it be much trouble to add an option for overclocking within the application, this way we could specify an overclocking rate.
For now, I suppose the best bet would be to release a 330 build and see if that works.
I deleted the other PCE.SIM (DOOEngine) file I had and made sure there were .PCE roms in the roms folder, still no luck. I even tried putting the 'DingooHuGo' folder in different directories, no joy.