Database Software

Hi, gurus! :)

Upon executing a process flow, I got the following error message:

RPE-01003: An infrastructure condition prevented the request from completing.
RPE-01038: Failed to evaluate expression null. Please modify the expression, redeploy and retry again.
RPE-01003: An infrastructure condition prevented the request from completing.
RPE-02227: Cannot test Control Center user OWF_MGR. This user must match the login credentials of the evaluation location configured on owning module.
RPE-01003: An infrastructure condition prevented the request from completing.
java.lang.NullPointerException

I suspect I got this error from improper use of parameters (just started using). I've searched for answers in the internet, still I am not sure how to efficiently and correctly use parameters. I'm dealing with this "literal" confusion. I would like to confirm the following:

1. If a local parameter is an integer, how should I set the value and literal field? (say, set value to 0, literal = true?)
2. How about for while loops? The condition is automatically a string. If I use the paramater par_loc, how should I write it (say, par_loc < 100).
3. For Assign operators, data type is also an automatic string. What if I want to have an integer value? Or maybe an integer value thru an expression? (e.g. par_loc + 20).

The questions above somehow summarize the activity I created.

I'll try to do more tests and research and give you an update if I found any solution.

Any help will be deeply appreciated. Thank you, gurus!

Manoy :)