Under most circumstances User Initiated Job events or SSIS package firings are bad ideas. The reasoning behind this is that it has very little collision detection. It's quite easy for multiple users to overwrite each other's files, truncate staging tables another instance was in the middle of using, things of that nature. With jobs the user may get timeouts or the like as another user is already using the job... and you may have overwrote variables the original job was using before the second user tried to fire the job.
That's why you're finding it so hard to implement. It should only be done with extreme caution.
That said, what are you trying to have the package do for you? We may be able to offer a better streamlined solution.
Never stop learning, even if it hurts. Ego bruises are practically mandatory as you learn unless you've never risked enough to make a mistake.
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