Once again.. why are you trying to pass the executionContext to the subprocess??
Read about the policies about copying process variables thru them...
You also can look in documentation for process/sub process interaction...
In this type of cases you sure resolve the problem copying only the variables.. for interaction!
I found my problem. You are correct that I had to pass the variable rather than the executionContext. I was getting error as I was not passing a serializable object in the executionContext.
Thanks for reply :)