This error message appears in planning mode and the heat maps do not work properly.
This issue is due to Cisco bug ID CSCse83815.
As a workaround for this problem, complete these steps:
In order to resolve this issue, upgrade the Wireless Control System (WCS) to firmware version 188.8.131.52 or the latest version, which is available at Cisco Downloads.
Wireless Location Appliance
Wireless Control System
WCS Errors, Warnings and Log Messages