Spears was supposed to play Warsaw July 24. By nixing the date, her last stop on her current Euro tour is now July 26 in Berlin.

Why is Brit skipping Warsaw? Her Circus tour has been doing great business all over the planet, and placed first in Pollstar’s midyear U.S. rankings, selling more than 614,000 and grossing $61.1 million. Worldwide, she occupies third place, selling 785,000 tickets and grossing $74.6 million. So don’t blame lack of ticket sales for her withdrawing from Warsaw.

On the other hand, money is often at the root of such changes. A publicist for the performer released a statement claiming a “contractual dispute” had not been resolved.

A posting on the show’s official Web site – BritneyKoncert.pl – said it will post refund information for ticket holders.

Click here for Pollstar’s midyear stats.

Click here for BritneyKoncert.pl.