Cross Section Labeling Error

I am trying to use the Cross Section Labeling tool within the Geopak Corridor Modeling tool, but as soon as I press the button, I get this error:

After I click the buttons, it obviously won't work. I think this error may somehow be related to installing Geopak SS3. Before I installed that, the tool was working. I am trying to use this tool while in MS 8.11.09.397 and GPK 8.11.07.566.

I didn't think installing GPK SS3 next to (different installation folders) would cause issues, but I can't think what else it would be. I have tried using the tool with different workspaces with no luck. There are others in the office that can use the tool, but they don't have GPK SS3 installed.

Any ideas how to remedy this? I prefer not to have to uninstall GPK SS3, but if I am unable to use the tool in SS2, I will have to.

Thanks,

Ken