1. A general rule would be to clear all cache through the admin-interface. If this does not work, try to turn on debug output, and make sure to turn on "show used templates". Now, when accessing the page in your browser it will list all the actually used templates for the viewed page.
You can now check if you edited the right .tpl file.
2. If you are using a image library to generate the images for the menu this would be a place to start looking. Check ini settings (<i>texttoimage.ini and image.ini</i>) and that fonts are where theyre supposed to be. Otherwise i would have checked the paths of the images in the menu. If you recently moved the site it could be they've been corrupted.
