Fatal error: Cannot access empty property

Hi,

Please let me know what other information you need. A developer is helping me build a site and we are using the GMap module. We have a list of nodes that have location information. The developer has created a view that will show the nodes on a map. If the view does not use the output from the location module, everything works without error (but there is nothing on the map), but if we use the output from the location module (which we want), then we get the following error:

Fatal error: Cannot access empty property in /home/content/g/l/u/siteadmin/html/modules/views/modules/node.views.inc on line 670

We were running Drupal 6.10 but upgraded to 6.11 and updated all the modules and we still get the same problem.

Drupal 6.11
Administration menu 6.x-3.x-dev (2009-Apr-25)
Advanced help 6.x-1.2
Content Construction Kit (CCK) 6.x-2.2
Fivestar 6.x-1.15
GMap Module 6.x-1.1-rc1
Location 6.x-3.1-rc1
Views 6.x-2.5
Voting API 6.x-2.0-rc2

Please let me know how we can resolve this or what additional information you need to help troubleshoot. Thank you very much.