Thank you for reporting this bug. We will make it our priority to review this report.
[CLOSED][3.??] Error when running Portal demo, Web Desktop Demo and etc.
Most samples can not be run in IE 7 and Firefox 3.5, but it's ok on google chrom 3.
For example, Web Desktop, Portal Demo, Array Grid Example.
All of samples are published in extjs.com.
Very strange, now it's work. Maybe all samples is updating.
Remember that the site was just updated, chances are you need to clear your cache. Marking as closed.
Twitter - @evantrimboli
Don't be afraid of the source code!