vRanger Pro, the successor to ESX Ranger, is supposed to be simple to use; which once it's set up, it seems quite simple; however when used with the VCB pluggin, if your iSCSI or FC connections are not set up correctly, you can get strange error messages, that just don't mean anything.
The first thing to do is to make sure that any multi-pathing software is configured correctly, so that there are not any additional paths to the devices in Disk Management (we had some which we inaccessible).
After removing and reinstalling the iSCSI initiator with Multipathing support, the issues went away, and the software works correctly.
It's also worth noting, that you don't actually have to edit the config.js file in the VCB config folder, as vRanger doesn't use that; however if you want to manually run VCB to see where any problems are, then you still need to configure this.
