when using the installed client it works fine but when I am running the screensaver version of the client it displays incorrectly (white page with text and links down the side of the page)
You need to add registry keys for the screensaver version of the application:
I believe it’s XiboClient.scr when installed as a screensaver, so you’d need to add extra keys for XiboClient.scr, or whatever you’ve called the screensaver file.