Batman: Arkham Asylum PLEASE HELP

hi all,
im pretty much stuck at this level for sevral hours now...

i'm passing through the chamber room and and go to the door, when i walk inside i got a ledge and then a vent, but i cant grapple or jump into the vent..

i went back and collected anything collectable in the botanical gardens, or at least i think i did, but i still cant seem to go through...

anyone got any ideas? :\

http://img509.imageshack.us/img509/8982/baastuck.jpg

please help