Thanks for your reply farshizzo. I did have Max shut down before running the installer. I get that error the first two times I try to save an OSG file and then Max crashes.
The reason I asked if there is something I'm missing is because the error persists even after uninstalling and reinstalling the plugin. I know some kind of file is saved in the system because all export settings from the previous install return when I reinstall the plugin. This is even after the old OSGExp folder is deleted.
I deselected everything but geometry and it still won't export. I've tried it with the default settings and that doesn't work either.