Party duels in Lineage 2

I can't seem to initiate a party vs. party duel at any time, no matter what. Each time I try, I only get a message saying "you can not send an invitation at this time", or something to that account. Everyone in the group is at full health (and full MP of course). We tried having the leader challenge the leader, even though it's supposed to be set so that anyone in a group can challenge anyone else, but no luck. What's going on here?

RTFM, man:
If any party member is in any of the following states, that party cannot request or accept party duels:
* When in combat or duel, or chaotic state
* When participating in the Olympiad Games
* During private store or private manufacture
* When HP/MP is below 50% (including death)
* When in a siege (clan or ally participating in a siege)
* When the one challenged to a party duel is a member of the challenger's party
* When in a zone where restarting is prohibited
* When inside a siege war zone
* When the challenge requester and recipient are more than a certain distance apart
* When there is no empty space in the party-use arena
* When the challenge recipient is in an opponent’s hall during a siege
* When riding something a strider or wyvern
* When in a peace zone or battle zone