Regarding the links, that seems to be indicating that the plugin isn't detecting the plugin you're using to create multiple networks (which I think is also what's causing the error in deleting roles). The code I wrote should be detecting the WPMN/NWP plugin, but it seems to be failing somewhere along the way in some situations (since releasing the updated version, I've found the issue you describe on one of my test installations).
I'll keep looking into all of these issues.
EDIT - I see you were posting another post while I was writing this. I've registered as cgrymala on the site you provided. I'll also check out the plugin in Opera, since you indicated that's the browser you're using.