Dungeon Explorer Warrior of Ancient Arts for DS.

hey.i'm stuck at the 'Necromancer's temple', floor level 1 of inside the temple.the door is sealed in the room where a 2-way portal appears to just outside where the ghost is.
it says: 'the door is sealed, maybe you've forgotten something.'i have no idea how to get it open.thanks for your help.EDIT: at this point, character level 20.

So tired of this question.. Walk close to the right side of the wall of that main hall. Your robot will start flashing, which indicated there is a secret entrance at where it is standing. Walk in the wall and there you are.

Why, have people personally contacted you about this question a lot? :-\

I have found this room (and one across the hall from it) but I still cannot open the portal. What am I supposed to do in this room other than kill everything?EDIT: Found the answer here, http://www.gamespot.com/ds/rpg/dungeonexplorerjashinnoryouiki/show_msgs.php?topic_id=m-1-41462393&pid=943058
It was in fact the room across the hall (on the left side of the main hall) and I couldn't get past/destroy the spikes to get the urn. The trick, which is now obvious, is to just walk through the spikes taking damage as you go.