Just wanted to pass on a recent experience. I was using C251.exe V3.20a and experiencing quite a few problems with an RTOS. Investigation at the assembly level revealed really screwed-up code. I was provided with the latest V3.20b which cleared up the problems. Anyone using V3.20a should seriously consider moving to V3.20b.
I called Keil. They sent the latest CD which had v3.20b on it.