'DefaultFileName' => $row_rstblinventory['InvImage'],
now, it is possible that the recordset is not on the correct row once the page submits to itself. That is probably why the tutorial has you add it to a hidden form element and refer to the hidden form element in the code.
That may be the solution... is the url paramater maintained through the submit so that the update recordset would be properly filtered?
The example where I defined the var just prior to the behavior should work the same as a hidden field or better since the hidden field would be latter in the document and the recordset constructs prior to the behavior.
I tried the hidden field and that also failed. Where is this tutorial you are speaking of?