What does "group does not have enough land credits" mean when trying to deed land to a group?

[Magnolia Ashbourne]

What does "group does not have enough land credits" mean when trying to deed land to a group?

[Griffin Ceawlin]

For the group to own land, its members must submit land contributions, donations that members make from their own personal land tier allowance. The group can own a total amount of land whose area equals 110% or less of the sum of all group contributions.

http://community.secondlife.com/t5/English-Knowledge-Base/Group-owned-land/ta-p/700079#Section_.3