Invalid cast from 'System.String' on Virtual Machines Tab on Datastores View

Hey everyone!  So I have the issue that popped up the other day and I think it may be related to an indivdual VM, but I was not able to find anything on the net about my error, so perhaps someone can help me out.

1. I log into my vsphere (4.1) client and connect to my vCenter (4.1).
   
2. I switch my view to Home > Inventory > Datastores.
   
3. I select my Datastore named "SAN1" (Netapp FC LUN).
   
4. I click on the "Virtual Machines" Tab.
   
5. I get the following error: Invalid cast from 'System.String' to 'Vmomi.Vm.Device.VirtualDeviceArray'.
   

When I select any of my other LUNs and the VM Tabs, I have not problems. However, when I flip back to "SAN1" and click on the VM Tab I get that pop up.  There are no indications of any problems anywhere else.  I can browse all the other tabs on SAN1 w/o problems, but the VM Tab always gives me that error, which is why I think I may have a VM problem.

Does anyone have any ideas?

Thanks,

Terry