According to this article, SpaceShipOne had problems on its last test flight.

…as SpaceShipOne detached from White Knight for an unpowered glide test, the radio chatter at Mojave Airport was suddenly tinged with alarm. ?Cut back on your trim, Mike, you?re way out of it!? a voice urged Mike Melville, the ship?s test pilot, over the com. SpaceShipOne, weighed down with lead ballast in its aft section to test the plane?s handling, was plummeting out of control, rolling over twice and falling 11,000 feet before Melville could wrestle the ship out of its dive. The rest of the trial maneuvers were canceled, and both craft came in for landings just as the desert sun was heating up.

Burt is making the usual noises about occasionally having unexpected things happen during flight test, and that’s why we have flight tests, and that’s of course true. It may be that it just didn’t behave quite as Melville expected, and that he’ll be better prepared next time, or it may mean some fundamental problem with the design. I’ve no idea, but it should at least give pause to any confident predictions of celebrating the Wright anniversary with a private manned spaceflight (even ignoring the regulatory issues).

I also think that this bit about XCOR is a little misleading:

…The engineers at the small, 12-person Mojave, Calif., firm, down the street from Scaled Composites, have designed the Xerus, a winged space plane intended to carry a passenger and pilot to suborbital space at Mach 4, powered by at least four kerosene rockets. The ship looks sleek in the drawings, the engineers have plenty of experience building spacecraft?but the company is totally broke. They work from an un-air-conditioned former Marine hangar and pay for their efforts out of their own pockets.

While it may be that XCOR is “broke” in a literal cash sense (I’m not privy to the books), the company has many assets (including their potential matching grant from the Air Force) that, combined with their talented staff, will be parlayable into investment. I’m personally confident that it will happen, sooner or later, and that they’ll remain alive until it does.