Don't bet on that casino in the Catskills opening anytime soon. The nearly-completed deal between Gov. Paterson and a Wisconsin-based Indian tribe for a casino in Sullivan County faces tough odds of being approved by the federal government and likely legal challenges from other Indian tribes that could keep it in limbo for years, sources said Wednesday. "My personal feeling is that it is not going to happen," said Assembly Racing and Wagering Committee Chairman Gary Pretlow (D-Westchester). "They're just too many obstacles."