Visual Studio 2005

I have a registration page that was created using a Wizard. There are currently 5 steps to my wizard.

Users enter info using a series of textboxes and dropdownlists in steps 1 and 2. In step 4, the info is saved to the DB.

Recently, I included the option to upload a pic in step 2 of the wizard. When it comes time to save to DB in step 4, I find that the 'pic' variable being populated from the FileUpload control is empty. Apparently, no file is being posted. Here's the error message:

Object reference not set to an instance of an object.

The code I have written works perfectly well outside the wizard. What is it I am missing that prevents me from properly processing uploaded files?