I believe you have to go in the lotro ini file in the documents folder and make sure that user specified port is set to 0 meaning it can use any port it wants. Second thing to get 2 instances to run on one PC, I have found Innerspace to work well. It also helps to have lotro on a C drive and a D drive. Helps with performance issues. One of the advantages of Innerspace is that you can tell it what CPU core to run each instance spreading out the load on cpu much more evenly as well dual monitors or even see both on 1 monitor.

You will also need the ISBoxer toolkit. It does alot in configuring Innerspace and makes it much easier to do. First time out can be a little rough but Lax has made some videos to help get you thru it. He has a trial setup so that you can play with it. You will need to setup a login so that they know you are a real person.

Also if you have questions on the ISboxer toolkit page, and about half way down the page there is a IRC chat link. If you find yourself stuck and unable to figure something out, you can go to that chat room and chat with other users and even Lax if he is around.

Introduction to Innerspace

There is the link to get you started and also to what Innerspace looks like when you run it.

Hope that helps.