In theory, no reason why that shouldn't work. You don't say what actually happens in your case.

• Does it hang after running blabla.exe?
• Does it not even run that properly?
• Does it exit immediately after running blabla.exe?

Maybe blabla.exe is not actually exiting. Perhaps it is waiting for some input.

If you could post a bit more of your code, and maybe tell us what the external program is trying to do, that would help.