The file you need to edit is the inc_top.asp file. The javascrtipt functions are in the header.
But the pop-up window should have the scrollbars on. When you install the smilies mod, you include this function in your files:function openWindow5(url) {
popupWin = window.open(url,'new_page','width=400,height=500,scrollbars=yes')
}
But if you don't have it and want to add the scrollbars, just add that piece of code in red to the function.