Computer virus theory on missile explosion

Did a computer virus cause the explosion of an Iranian ballistic missile, capable of carrying a nuclear warhead?

The story that is doing the rounds claims that on the 12th November 2011 a missile exploded in an Iranian army base. A number of Iranian officers and rocket experts were killed.

The Stuxnet worm is considered to be the culprit.

So far the facts seem rather vague, as the coverage of this event stems almost entirely from a report on one website, that being Debkafile. This site appears to be "unabashedly in the hawkish camp of Israeli politics" and uses unattributed sources extensively.

Taking this main report on its merits, let's see what the 'facts' are, versus the 'theory'. I'll assume that the following four details are accurate:

1. Maj. Gen. Moghaddam presents a new type of warhead to experts.
2. He runs a computer simulation on a system attached to the missile.
3. The missile explodes, killing over one dozen people.
4. The extent of the explosion means that there are no witnesses and little physical evidence.

The Debkafile report also notes the following:

1. The missile exploded because the computer sent it an order to do so.
2. Iranian intelligence have two theories:
• Western or Israeli intelligence services planted a technician, who sent the signal ordering the missile to explode.
  [Note: I think the reporter meant that the technician programmed, rather than signalled, the computer.]
• The computer was responsible, having been infected with the Stuxnet worm.
3. Iranian intelligence considers the second theory (above) to be more plausible than the first.

To summarise, a missile has exploded in an apparent accident and there are no living witnesses. The computer involved is completely destroyed, as is the missile.

Somehow Debkafile is able to deduce that the computer sent the order to explode, despite no apparent evidence to support this. This is a significant problem with Debkafile's report. It contains no attributed facts, just statements of fact without any evidence.

Which of the following do you think is more likely?:

1. The missile exploded, accidentally.
2. A spy programmed a computer to explode the missile.
3. A computer virus programmed a computer to explode the missile.

It's coming to something when the idea of computer viruses exploding nuclear-capable missiles is more plausible that accidents or more mundane methods of sabotage.