Here are two news articles on the question. The first (here) details the Town of Ledyard’s crusade to collect taxes on the non-Indian owners of the slot machines used at Foxwoods. An excerpt:

Other grievances, not surprisingly, involve money – particularly the sovereign nation’s deal to pay the state a quarter of its slot machine revenues instead of local taxes on reservation property in the northeastern corner of Ledyard.

Though the town grudgingly concedes it can’t collect these revenues, it has for years been trying to levy taxes on personal property owned by non-Indians on reservation lands – specifically slot machines that a New Jersey company leases to the tribe.

Six years ago the tribe and Atlantic City Coin & Slot Service sued Ledyard to block these taxes, claiming such municipal action disregards well-established principles of federal Indian law and interferes with the tribe’s gaming operations, self-determination and sovereign immunity.

So far, the town has spent $900,000 fighting the litigation – a whopping sum that could have been used to hire teachers, repave miles of roads or buy thousands of new library books.

The second (here) includes a quote on the Indian law implications of the case:

Bethany Berger, a professor of Indian law at the University of Connecticut School of Law, said that taxation of non-Indians and their property on tribal lands is complicated. Berger, co-author and member of the editorial board of Felix S. Cohen’s Handbook of Federal Indian Law, the pre-eminent treatise in the field, does not think Ledyard’s case is a strong one.

“The machines are leased by the tribe as part of this federally regulated business that the tribe has a big interest in,” she said, adding that the interests of the state of Connecticut in the matter may not be as strong as Ledyard officials hope.

“With respect to state interest, it can’t just be revenue-raising interest,” Berger said. “Ledyard wants to make money by taxing the machines, and that’s not the kind of interest that’s really important. The federal interest is very strong because of the Indian Gaming Regulatory Act and the tribal interest is also strong because this is the business that provides most of the tribe’s revenue.”