Jason,
Make sure your metadata USER field has a keyed list with the key OBFILENAME. It is from that key (OBFILENAME) that the proc in question is setting the value of fileName variable.
If the OBFILENAME does not exist in the USERDATA metadata field, then the variable fileName will not get established thus the error you see.
Jim Kosloskey
email: jim.kosloskey@jim-kosloskey.com 29+ years Cloverleaf, 59 years IT - old fart.