VUGEN script in PC does not proceed beyond VUser Initialize and fails to RUN

I have a problem of getting Some VUGEN scripts from a recent scripting task to RUN in ALM Performance Center having worked perfectly well in VUGEN. 

I have 10 scripts that work in VUGEN - 50% Fail to Run in PC

When transferred to ALM Performance Center. Some of these scripts function and some do not make it to the Run Stage. The VUsers initialize but they TimeOut because they have not progressed to run the script.

I increased the delay for time out to 3 minutes and this had no impact.

Any assistance would be greatly appreciated.

Paul G