I have a Flow that calculates commissions for real estate agents based on their possission in an agent hierarchy.  I would like the flow to be available via a site to access outside of the native salesforce environment.  The Flow works as desired when triggered from a Tab or Button inside Salesforce and runs with no errors, however when accessed via a Site, the initial screen is displayed, but after enteringa  value for the transaction to calculate from, an unhandled fault occurs.  The Flow accesses custom fields on the User Object as well as fields from another custom object to calculate commissions.

My hunch is that it is a permissions issue regarding the User object, but I am unable to solve the riddle.  Your help is greatly appreciated.

I am a new learner in Sales Force, was trying to create work flow rules and its missing under Setup Option. Please help