Error: IIS6 Error EventID 1059 and 1021

Just a had a problem with an application pool which always crashed after start. The application pool worked some days ago without any problems. After watching den System Eventlog I got the Error with Event ID 1059 and a Warning with Event ID 1021.
I had this problem on a Windows Server 2003 SP2 with all the latest patches
EventID 1059
Event Type: Error
Event Source: W3SVC
Event Category: None
Event ID: 1059
Date: 27.05.2011
Time: 11:49:31
User: N/A
Computer: WEB-WIN
Description:
A failure was encountered while launching the process serving application pool 'www.domain.ch'. The application pool has been disabled.
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

EventID 1021
Event Type: Warning
Event Source: W3SVC
Event Category: None
Event ID: 1021
Date: 27.05.2011
Time: 11:50:01
User: N/A
Computer: WEB-WIN
Description:
The identity of application pool, 'www.domain.ch' is invalid. If it remains invalid when the first request for the application pool is processed, the application pool will be disabled. The data field contains the error number.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 2e 05 07 80 ...€

The Solution for this problem is very simple. Just reset the password of the specific IUSR and don’t forget to reset the password for the application pool identity.