Most likely, this is because you have not specified this functions availability in the Function Text Property. Make sure that you have entered the appropriate variable to display the function and try again. Also you may want to check the Display HTML and confirm that you have specified the function there as well. When a function is displayed it first gets it directive from the property to show or hide the function. After that it uses the Display HTML property with the correct variable to display access to the function. Finally the Function Text HTML property is used to provide a link to activate the function in a window.
This is because there is no display name set up for the user that you are currently logged in as. Go to "Site Settings"/"View Information about Site Users" and add a display name to your account.
This is usually because they have no Display Name. Have the user edit their information to correct the problem.