Old post – here are the steps:
Open the .skn file in any text editor. Notepad works fine.
5. There are two lines that start with "frameset cols=" in the skin file. Default is <frameset cols="220,*" etc.
6. Change the 220 to the number of columns you want. Make sure you change it in both places.
7. Save the skin file.
This worked perfectly -- thanks so much for your help!