error on add new values on the fly

I'm getting an error when adding new values "on-the-fly" on a site I built with PHPRunner 6.2:
Fatal error: Call to a member function getLookupTable() on a non-object in C:\wamp\bin\apache\apache2.2.22\htdocs\443\showingsystem\include\commonfunctions.php on line 1825
Has anyone run into this before? I have the tables: companies, agents, showings
I allow users to add companies and agents on the fly. When entering a new showing the user can add a new "agent" and from there can add a new "company" if needed. Once you try to submit the new showing after adding a new company/agent on the fly you get this error.