I am sorry to hear your experience, and I hope it was an anomaly. I have eaten dinner at Boma four or five times, most recently in March 2009, and it has consistently been one of my favorite Disney restaurants.
To the original poster, I would not let your opinion of Tusker House dissuade you from trying Boma. Though the offerings are somewhat similar, Boma is a superior establishment. I liked Yak & Yeti when I tried it with my family a year or two ago, but I would choose Boma given the chance.
Good luck!