Error in I_STEP = 3

Hi all,

I am validating the user input in I_STEP = 3 and popping up a message. However, after the popup , the query continues to get executed. I have tried to use "Raise <exception>" . However, in this case , I get an error message after the popup saying that "There are invalid values for the variables". Is there anyway to catch this error message. Please let me know if there is any other alternative.

Thanks,