Another procedural error on the part of the plaintiff states in the Microsoft antitrust trial has prevented evidence from getting into court. And that evidence, involving a specialized operating system called Windows XP Embedded, could have made the states' case. On Thursday, lawyers representing the nine litigating states and the District of Columbia canceled a May 15 XP Embedded demonstration after being reprimanded by the judge. U.S. District Judge Colleen Kollar-Kotelly--under pressure to resolve the case on schedule--said the states' legal team had failed to give the court proper notice about the scope of the demonstration and the amount of information Microsoft would have to sift through to respond to it.

The demonstration could have resolved two issues for Kollar-Kotelly: whether Microsoft could develop a "modular" version of the operating system without so-called middleware, such as the software giant's Internet Explorer browser and Windows Media Player, and whether Windows XP Embedded could be used as the basis for a custom version of XP that would run without any serious loss of performance.