you should use this:
PHP Code:
// ###################### Start coloredusers #######################
$post[specialusername] = $post[username];
if ($post[usergroupid] == 6) { $post[specialusername] = "<span color=\"#cc0000\"><i><b>$post[username]</b></i></span>"; }
if ($post[usergroupid] == 11) { $post[specialusername] = "<span color=\"#000000\"><b>$post[username]</b></span>"; }
if ($post[usergroupid] == 10) { $post[specialusername] = "<span color=\"#0000ff\"><b>$post[username]</b></span>"; }
if ($post[usergroupid] == 7) { $post[specialusername] = "<span color=\"green\"><b>$post[username]</b></span>"; }
if ($post[usergroupid] == 2) { $post[specialusername] = "<span color=\"#0000ff\">$post[username]</span>"; }
if ($post[usergroupid] == 5) { $post[specialusername] = "<span color=\"green\"><b><i>$post[username]</i></b></span>"; }
// ###################### End coloredusers #######################
and be sure you use $post[specialusername] in your postbit