system.cannotunloadappdomain   

My system is Windows 2000 SP4 and .NET 1.1
After i upgraded to .NET 2.0, error occured.

Error from Event Viewer:

Event Type:	Error
Event Source:	ASP.NET 2.0.50727.0
Event Category:	None
Event ID:	1000
Date:		7/17/2008
Time:		5:48:07 PM
User:		N/A
Computer:	AACMSAPP1
Description:
aspnet_wp.exe  (PID: 1424) stopped unexpectedly.

Event Type:	Error
Event Source:	.NET Runtime 2.0 Error Reporting
Event Category:	None
Event ID:	5000
Date:		7/17/2008
Time:		5:48:00 PM
User:		N/A
Computer:	AACMSAPP1
Description:
EventType clr20r3, P1 aspnet_wp.exe, P2 2.0.50727.213, P3 450b6662, P4
mscorlib, P5 2.0.0.0, P6 4333ab80, P7 482, P8 27, P9
system.cannotunloadappdomain, P10 NIL.

I found that the Description means:
P1 - Proc Name          - aspnet_wp.exe
P2 - Version            - 2.0.50727
P3 - Timestamp          - 450b6662
P4 - Asembly Name       - mscorlib
P5 - Assembly Version   - 2.0.0.0
P6 - Assembly Timestamp - 4333ab80
P7 - Unknown            - 482
P8 - Unknown            - 27
P9 - Namespace?         - system.cannotunloadappdomain
P10- Unknown            - NIL

I have tested for many servers, only the production server has this
issue.
I have already reinstall IIS 5, .NET 2.0 and run the
aspnet_regiis.exe,
and iisreset. The problem still here...

I have found information about appdomain,
i think the problem is closely related to the configuration of the
application domain,
but i don't know to to unload or creating a new appdomain for my
application.
Is it necessary to write a new page to unload and create the
appdomain?

Any suggestions for this issue? Thanks.

date: Mon, 21 Jul 2008 02:48:17 -0700 (PDT)   author:   unknown