Fact is a lot of the people involved with opening king Tuts tomb died in a relatively short period after the opening of the tomb. Coincidence? There is no such thing as coincidence and besides that it's boring!
I don't believe in black and white yes or no answers. The answer to a lot of intriguing questions is usually liquorice all sorts. So what about this curse thing?
The ancient egyptians inherited a lot of scientific and esoteric knowledge from their [atlantean?] gods/rulers. In my view it is very possible the priesthood who did most of the burying used some of this knowledge - even at Tutanchamons times when there were little or no 'gods' left - to prevent graverobbers to enter or at least enjoy their treasure for long. They might have planted some bacteria or virii in the foods often buried with the deceased or might even know a way to enclose some "ethereal" energy in the tomb which logically [greetings to mister Spock] would affect anyone opening and entering the tomb. Another theory is that the air inside the tomb which would be some 3000 years old wasn't to healthy to breathe. This makes perfect sense to me. The grave openers might have been to eager for gold to take care and give the place a good let the wind blow through first. It is also very possible some of the people involved would have died anyway without being involved with opening the tomb. This what if question will surely never be answered, so we must include a couple of would have died anyways in our assumptions.
I'm no microbiologist but the bad air theory sounds simple and logical - Spock raises an eyebrow - and can easily be combined with the bacteria or virii theory. But: did all of the 'cursevictims' die of one or two causes? No they didn't. The only way we can keep this theory upright is to assume the bad air had a general weakening effect, something like aids. This also brings down the planted bacteria or virii theory. Whats left? Only the startling assumption the priesthood had the ability to call on a power beyond our understanding: the so called curse of the faraos.
Some medium healers and priests radiate a "higher energy" through their hands unto the populace. In my experience this energy is from The Source of Love. This energy is best stored in plain tap or mineral water and is said to retain its positive workings for a long time at least. If this energy can be experienced and has a healing quality it is logical to assume an inverted variant, a destructive equivalent, can be called upon by some priests and stored in matter appropriate. If the positive energy of this kind raises the bodies resistance, the counterpart would lower the resistance of the body and maybe even create enough reduction in the strenght of the body of light to allow evil earthbound spirits to do their thing. This would allow for relatively rapid and varied causes of doom to befall on those exposed to the radiation.
You could take this line of reasoning even one step further. The "evil" priests selected a or some volunteers to die during the embalming period and cast evil unto graverobbers and other unexpected guests from the other side. Nightmare on Valley of the Kings part VI. Yeah, right!
I'm a little weard but not crazy so you can expect some of the above to stand its ground in court. Think big, be a genius!
Disclaimer: i'm not a scientist - which is an advantage up to some point - and have a bad memory. I know it would help if i could cough up the facts of who died when and of what cause. I read the books concerning Tuts tomb a long time ago and i can't recall their titles or authors but it should be easy to find in any public, school or university library [i'm to lazy]. I limit myself to overall conclusions and giving my comments on generally accepted theories and public knowledge. I do not claim to know it all but egyptologist don't either. If you have any solid information to complement my knowledge i would like you to e-mail me. I'll mention your name on this page and in my last will and testament.