Export of fees/fines not working

Overview:  When I attempt to create an export of fees/fines for a user who does have fees/fines, I get an error (as described below). 

Steps to Reproduce:

1. Log into Juniper BugFest as an admin.
2. Go to User Details for a patron with fees/fines (for example, Aaron, David J with barcode 0000087375, who has 2 outstanding fees/fines). 
3. Select Actions=>Export fees/fines.

Expected Results: Export including 2 fees/fines.

Actual Results:  Green success toast stating "Export in progress" appears along with red error toast stating "Something went wrong" as shown below...