Authorizing offline computers can be difficult.  Try these instructions, which I found recently and were written by a Line 6 moderator . . .

First off, you would need access to a computer that is connected to the internet so that you could download the most recent version POD Farm 2.51. You can download them from the links below:

Windows POD Farm 2.51:

http://line6.com/software/readeula.html?rid=4147

Mac POD Farm 2.51:

http://line6.com/software/readeula.html?rid=4149

Once you have downloaded this file, you will need to install it onto your computer and then authorize it. We have a video tutorial that will show you how to download and install POD Farm, and then use the License Manager rto authorize your computer:

http://line6.com/support/docs/DOC-2499

Once you have installed it onto your online computer, you will need a way to bring the POD Farm software and authorizations to your offline computer, by burning the file to a CD/DVD or using a external hard drive/flash drive. After obtaining your transferrable medium, you will need to put the POD Farm 2.51 file that you downloaded on the medium as well as the authorization files. For instructions on how to locate and transfer the authorization files, check out the video tutorial we have for this process located towards the bottom of the following document:

http://line6.com/support/docs/DOC-4738

Once you get the file onto the transferrable medium, bring it to the offline computer and install it. Once POD Farm is installed, you can place the authorization files in the same place that they were located in on your online computer to authorize POD Farm 2 on your offline computer