I am afraid I do not think anyone on this forum knows. I have been trying to get answers to the same problem myself.
I have been having the same problems with a new ccf file, and learning IR codes from 2 remotes for the same device (grundig TV. One remote (the original) and the other ( Maxview 2 in1) both control the TV independantly, the 5450 with PDAWin learns commands from both, and they appear in the ccf file, almost but not quite identical. BUT the codes learned from the original grundig do not work from PDAWin while the codes learned from the 2in 1 unit do.

PDA Win does not seem to work with 5450, I think it is going to be a case of spend the cash and buy the new Pronto.