I don't know if anyone else answered this....I didn't find the actual cause of Dan's death on danhartman.com, though I didn't look too thoroughly for it. It does mention that he was HIV-positive, but I remember at the time of his death, HIV/AIDS was not the publicized cause (I seem to remember reading at the time that it was a cerebral hemmorage or something like that). I liked his work; "I Can Dream About You" was a very good one and one of the better "disco" songs.
Bryan Not to be morose, but....another musician death that may have slipped under the radar screen unnoticed was that of Nicollete Larson. She was an artist of considerable talent and a protege (and friend) of Neil Young, I believe.