I installed Plesk on 64-bit version of Windows Server 2003. But all my sites fail with

I installed Plesk on 64-bit version of Windows Server 2003. But all my sites fail with
`Service Unavailable`
How this can be fixed?
RESOLUTION

The source of this problem is in IIS works in 64-bit mode by default. The problems related to IIS functionality in 64-bit mode are described in the following article:

http://support.microsoft.com/?id=895976

IIS 6.0 supports both the 32-bit mode and the 64-bit mode. However IIS 6.0 does not support running both modes at the same time on a 64-bit version of Windows.

1.
To switch IIS to 32-bit mode use the following command:

cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 1
2.
To switch IIS back to 64-bit mode use the following command:

cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 0

Keywords: Could not load ISAPI 64-bit 32-bit mode IIS

[Info] Does Plesk work on x64 architecture?

[Info] Does Plesk work on x64 architecture?
RESOLUTION
Yes, Plesk can be installed and does work properly on Windows x64 since Plesk 7.6 for Windows. However Plesk is 32 bit application therefore it switches IIS to 32 bit mode.

Note: As a result you cannot install SharePoint Server and Services 3.0 on Windows x64 with Plesk.

[FIX] COM Server application errors appears after SP1 for Microsoft Windows 2003 had been installed

[FIX] COM Server application errors appears after SP1 for Microsoft Windows 2003 had been installed.
SYMPTOMS

The launch and activation of security descriptor for the COM Server application with
CLSID is invalid. It contains Access Control Entries with permissions that are invalid. The requested action was therefore not performed. This security permission can be corrected using the Component Services administrative tool.
RESOLUTION

Permissions for DrWeb DCOM object should be corrected. It can be done following the steps below:

1. Go to Start, Administrative Tools, Component Services, Component Services, Computers, My Computer, DCOM Config, DrWebCom

2. Right click and select Properties. Select Security tab and change Launch permissions to Default.

3. Restart DrWeb.