Count your beginning and ending parenthesis, they need to be equal:
HTML Code:
<if condition="in_array($forum['forumid'], array(41,42,55,43,44,53,45))">
not
HTML Code:
<if condition="in_array($forum['forumid'], array(41,42,55,43,44,53,45)">
But, why are you even doing that condition when you end it right after you do it? It's a 'blank' condition, so why put it in? Just put in the other (but make sure the parenthesis add up, as I said).