On a computer that is running Microsoft Windows Small Business Server 2003 or Microsoft Windows Server 2003, you may experience any one of the following symptoms:

*** STOP: 0×00000020

Not all “Stop 0×00000020″ errors are caused by the problem that is described in this article.

CAUSE
This problem is known to occur on servers that are running Symantec pcAnywhere 11.5 with Symantec AntiVirus 8.x or with Symantec AntiVirus 9.0. An updated version of the Symantec Event Handler driver (Symevent.sys) causes this problem. The Symevent.sys driver is installed with pcAnywhere 11.5. The Symevent.sys driver causes the Symantec real-time protection drivers to generate the “Stop 0×00000020″ error.

RESOLUTION
To resolve this problem, download and install the latest Symevent.sys driver. For more information, visit the following Symantec Web sites…

[Continue reading Microsoft Knowledge Base article 905539]