My first thought is that your positioning problem is because you've followed the directions for embedding a menu in a table cell, but instead of a table, you have your main menu inside of a div that's nested inside of another div. The menu doesn't like to be put inside of divs. Can you remove the main menu from the divs and position it using the menu system's built-in positioning functions?
The followscroll problem is because you've set position="relative"; Relative positioning and scrolling are sort of mutually exclusive (i.e., a relatively positioned menu won't follow the scroll).