Hi Putnamsam!
I'm guessing that you have a SharePoint list with usernames in it and that you have a data connection that loads that list on open. Make sure the data connection is set to load on open.
Do you set the username to a field on your data source or are you just using the username function in your rule?
To debug your form load rule, I suggest adding dialog popups. Who knows, could be a case sensitivity issue. Don't forget that xpath is case sensitive so if those usernames in your sharepoint list aren't all in lowercase, your comparison will fail.
Best of luck!
PS> how bout them Seahawks?