Full message:

Unexpected Error
An unexpected error occurred in the current procedure. The process will be cancelled.
An error has been logged which may be useful to the developer of this software.
OK

In the System Errors and Crash List (press Shift-Ctrl-L at main screen), the 2. Errors tab shows:
Date: 7/25/18
Time: 1:50PM
Station: 2
Store: 1
Procedure: SalesEntry
Routine: SetPaymentDetail
Activity: add(PayItem)
Error: 90
Value: [blank]

The same thing happens with Cash or Credit Card payment types. Reprinting existing sales receipts does work as expected.

Troubleshooting techniques that did not work:
Receipt Printer troubleshooting including registry-level removal and reinstallation with newer driver version 4.51.
.NET cleanup procedure
Updating Quickstore from 2008-3.12L to 2010-3.34M
Checkdisk
sfc /scannow

Resolution:

Maintenance menu, Recover Damaged Data Files. In the file list, select only the following files, then OK, Yes to confirm:
Payitem
Payment
Paymethd

After this procedure completes, click File menu, Printer Setup, Sales. Ensure the correct printer and model are selected. Do the same thing on each of the print types so they're all set correctly.

Test the operation again.