CheckOut/Edit a GPO returns the error "There is already an object named 'ch' in the database. " (4372468)

CheckOut/Edit a GPO returns the error "There is already an object named 'ch' in the database. "

Trying to Check out/Edit a GPO returns the error "There is already an object named 'ch' in the database. "
The error prevent to continue with the GPO modification and it affects all GPO. 

It has been  determined that there is a defect in the stored procedure GetItemModificationSchedule script.

A Defect request has been submitted to resolve this issue in a future version of GPOADmin. 
Defect ID VSTS000437754
The fix was included in version 5.18 update 1 if you can't upgrade there is a SQL script to fix this see workaround below.

Workaround: 

The script provided should ONLY apply to GPOADmin 5.18 RTM and only if you cannot upgrade to GPOADmin 5.18 update 1. This script should not be applied to any GPOADmin 5.17 versions or earlier, and also should not be applied to GPOADmin 5.18 Update 1.

As the full correction for this issue is also included in GPOADmin 5.18 update 1. At this time the best option would be to move to update 1. Only use the SQL script if this is not possible.