You know I have never heard of that problem, so its a first for me. If anything it would most likely be under the clinets settings folder. It should most likely be a .gif file, all you need to do is open it with a Text program and you should be able to read its contents and edit them as you see fit.
Remember To Back Up the Original file before you do this
The only issue you might have with a Lan and this is that file most likely needs to be the same for each system