Hi Folks,
I would suggest, in GNS3 you only need to setup the path for VBoxManage utility using the the Edit -> Preferences dialog box if you installed VirtualBox into a non-standard location and then you can add the virtual machines which should be created with VirtualBox.
check in the menu Edit > Preferences to set your desired Paths (in General sections) and to check the paths for the binaries (dynamips, vpcs, iou, virtualbox…)