Welcome to the frustrations of working locally and live with FTB.
This is something that has been raised in the core team and I believe they are looking for an answer.
You see, most people who have their network with dynamic IP addresses, they don't have IPs configured so when they setup their sites locally -it's using a Virtual Directory instance. So it works like localhost/dnn/ and the browser displays http://www.localhost/dnn. If you want to view across network you need to then set the alias in the portals table to also be your IP which is typically a 192.168.100.2 or whatever number assigned to your machine when you turn it on. (and this can change when something happens on your network which might be ok for small companies with just a few computers, but causes headaches for larger intranets, so they use Fixed IP or domain controller environments)
The problem is that with the editors is they put in that path and when you go to package up upload your db and such - it's remembered it and you need to then go in and modify these files when live because some hosting companies use IP based IIS and put in the full path of the website, using domain or IP controls which then render the site as a full domain, not a virtual directory.
I probably haven't explained in the full technical detail, mainly because I don't know how, but this is what is happening in your instance and is being addressed through DNN but not sure when it will be an enchancement.
The core team fixed up the issue with skinning by putting in that skin path reference in front of images, as this used to be a problem with skinning. But it's not any longer, so I'm not sure how they will resolve it but it was brought up in discussion only last week as many people are using this method of updating their sites.
I don't have an answer because everything I think of still means double handling, unless you set your network up to be IP controlled and not use virtual directory to manage your local instances..
Nina Meiers