check your wordlets mods in your cp.
in my 6.2.1.1 my wordlets mods look like this
'ubb_code_hide' => 'Hide - UBB-Code hide-text insert',
'hide_unhidemessage' => 'Unhidden message for you:
',
'hidemessage' => 'Hidden Message - Must Reply to see it.',
I think you have to add ' and ' bettween the first words in your wordlets_mods
hope this helps you.