Error 6909 happens running reports and customer cannot run the particular report until the roidetail table is cleared.
Roidetail is a temporary table used by reports
Make sure noone is Running reports and then run the following statement against the application db.
Delete from roidetail
This will clear the data and the client can run the program again.
BUG 37612 reported for version 2015. Hot fix available for 2015CU1.