I believe Schill means others, as in other parties, but I might be wrong the numbers for Schill look near the normal for the vote of "others" in German polls.
I know Jens has already answered this question, although I will add the address for the Wikipedia article on the original "Schill Party" which expelled Schill in December 2003 (reminds me of the "Connecticut for Lieberman" party being taken over by Lieberman opponents) according to Wikipedia (yeah, I know anyone can edit that site, but I'm hoping these articles are accurate). I thought I might mention, however, that the numbers for Schill in the original post on this thread were for the last election rather than a poll. Although 2.6% of voters in the Bremen state election voted for "Others" parties as Wikipedia defined them in the 2003 election Bremen state election according to Wikipedia.