(Part 2: The Answer)

The Pittsburgh Post-Gazette version adds an angle that helps to make sense of it:

Two Oklahoma Indian tribes that claim ancestral roots in Pennsylvania say they will file suit in federal court to get their lands back unless Gov. Ed Rendell and the state Legislature agree to give them other suitable property where they can start gambling operations. ... Kahrahrah said because the Legislature was gearing up for a debate on expanding legalized gambling in Pennsylvania, it was time for the Indians to make a play for property. He said the Indians are researching ancestral properties elsewhere in the eastern portion of the state, including near Philadelphia.

According to this, the land claim is more of a threat, intended to cow the state into granting the tribe land for a casino. The bad PR of saying they want a casino could hurt the land claim case, but it could also make the land claim case more fearsome (especially given the courts' tendency to side with Native Americans), thus motivating the state to settle out of court.