Resolve error 12 "Variable 'aiop' Is Not Found" when updating SendSuite Xpress

Products affected: SendSuite® Xpress

Issue

When installing the SendSuite Xpress 2.90 update, the following error message is displayed:
 
Program error: Attempt to execute Application Upgrade for v9.80/v2.80 was not successful.
Error #:     12
Description: Variable 'aiop' Is Not Found.
Module: Applyvalues (frmswin.applyvalues)
Line #:     56

The program will now restore any files changed to their original state.

Cause

Fields are missing from one of the SendSuite Xpress database tables.

Resolution

UPDATED: August 30, 2017
If you experience this issue, contact software support.