Blasted things, those oopses.
Depending on your set up, before or after a scan, you designate a location where you want the receipt, business card, or whatever, saved. 'C:\Documents'. Also, you select which format is required, pdf, jpg, etc. I name my scans for ease in finding them. '9-25-10 Joe's Diner' If you do lots of shops, you may want to have folders for each MSP and file the proof that way. 'C:\Documents\NameyourMSP'.
Then, when you're in the report, you can 'browse' to the location, select the receipt, and upload it.
If you continue to get Oops and can't submit, there's a link for technical support. Also, there's a link to contact the scheduler so you can let the MSP know what's going on.