This line
$result = mysql_query("SELECT title, changedate, date, author, pagename, document, sideheadline, sidedocument FROM $tablename WHERE id=$pagenumber");
Should look like this
$result = mysql_query("SELECT title, changedate, date, author, pagename, document, sideheadline, sidedocument FROM $tablename WHERE id=$pagenumber") or die(mysql_error());
I can garuntee it's not got a parse error in it.