For people in the same frustrating position that I was. Here is how to solve it. I found a thread that said the issue might be due to the backup having an operator/voicemail number already defined, but didn't explain how to fix it. So what I did was right click on the first start popup, then select inspect. Then delete the html from the inspector for the popup, then you'll have to delete a few more things by just hitting delete until all the backdrop stuff is gone. At this point you can navigate through the menus. Go to extensions and delete any extension in the 900's, I'm not sure if that was needed, but it was part of what they said in the other thread. Next you need to go to settings, parameters, then in the search box put operator. Double click this and change the operator to 0. Refresh the page and then you will be able to click through the welcome menu.
What's frustrating is that the error is completely misleading. On top of that, there is a page on the welcome menu for setting both the operator and the voicemail, so why not allow you to change it from there when you are importing from a backup so that we can avoid this issue.
Also, the new dashboard really is very nice!!