AMD was an extreme latecomer to the quad-core market, much to the benefit of their primary competitor, Intel. They need to make up a lot of lost ground, which right now is difficult as they are unable to meet demand for Barcelona. As such, they are claiming that the following quarter will see tremendous boosts to shipments.

While specific volume isn't mentioned, they do say they expect to ship out “hundreds of thousands” of units before the end of the year:

“While our initial production ramp of quad-core Opterons has been slower than anticipated, we expect quad-core Opteron will be widely available by the middle of this quarter; and, we expect to ship hundreds of thousands of quad-core processors this quarter into the server and desktop segments,” said Dirk Meyer, chief operating officer of AMD
Despite the advantages in design Barcelona has over quad-core Xeons, if they are unable to supply what demand there is it will be impossible for them to compete. Hopefully the issues will be resolved, particularly before they begin trying to push Phenom. A paper release is the last thing AMD needs right now.