Execute one of the scripts below in the Lansweeper configuration console under Lansweeper\Database Scripts. Copy and paste the code and hit the "Execute sql script" button.
Computers:UPDATE tblCompCustom
SET Location = web40AllIPLocations.IPLocation
FROM tblCompCustom INNER JOIN
web40AllIPLocations ON tblCompCustom.Computername = web40AllIPLocations.Computername
Devices:UPDATE tblCustDevices
SET Location = web40AllIPLocationsDev.IPLocation
FROM tblCustDevices INNER JOIN
web40AllIPLocationsDev ON tblCustDevices.DeviceKey = web40AllIPLocationsDev.DeviceKey