I am set up as webmaster on the site, when I log in and click the Notification button I get a blank page no headers or anything. I have created a registered user ID and log in with it, when I click notifications it comes up with headers and list of thing to be notified, like it is supposed to. I have cleaned the cache and tried it on a different computer, still the same thing. I have checked group permissions, and user settings. I can't see anything out of the ordinary. I am sure it is something simple I am over looking.

Try to compare modules/blocks that are visible to you and NOT to the registered user. Sometimes, especially when you're using PHP5 and have older modules, if the block/module is not compatible with PHP5, you'll get a blank screen.

Once you identify the modules/blocks, remove them and see which one potentially is the offending one. Then you could fix it.