Method not found: GetNamedPermiss ionSet() error on installing .net3.5

[Aled G]

Hi,

After upgrading to .net 3.5, my web app is giving the error on
all .aspx pages:

" Method not found: 'System.Securit y.NamedPermissi onSet
System.Web.Http Runtime.GetName dPermissionSet( )' "

....on an app which worked just fine before.

This is on XP SP2, IIS 5.1. Have tried aspnet_regiis -i, reinstalling
IIS, and reinstalling the .net framework.

Stack trace and event log entry below.

At a loss what to do next - don't want to reinstall everything as this
is my development workstation. Any further suggestions welcome.

Cheers,
A.
--
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 03/01/2008 13:53:49
Event time (UTC): 03/01/2008 13:53:49
Event ID: df4c8c8fb96348f c8f79fa0c416c51 0c
Event sequence: 9
Event occurrence: 6
Event detail code: 0

Application information:
Application domain: /LM/W3SVC/1/Root/
***myapp***/-1-128438410780466 912
Trust level: Full
Application Virtual Path: /tinyvan
Application Path: C:\Projects\*** myapp***\
Machine name: ***mycomputer** *

Process information:
Process ID: 604
Process name: aspnet_wp.exe
Account name: ***mycomputer** *\ASPNET

Exception information:
Exception type: MissingMethodEx ception
Exception message: Method not found:
'System.Securit y.NamedPermissi onSet
System.Web.Http Runtime.GetName dPermissionSet( )'.

Request information:
Request URL: http://localhost/***myapp***/login.aspx
Request path: /***myapp***/login.aspx
User host address: 127.0.0.1
User:
Is authenticated: False
Authentication Type:
Thread account name: ***mycomputer** *\ASPNET

Thread information:
Thread ID: 1
Thread account name: ***mycomputer** *\ASPNET
Is impersonating: False
Stack trace: at
System.ServiceM odel.PartialTru stHelpers.get_N eedPartialTrust Invoke()
at
System.ServiceM odel.PartialTru stHelpers.Parti alTrustInvoke(C ontextCallback
callback, Object state)
at System.ServiceM odel.Activation .HttpModule.Pro cessRequest(Obj ect
sender, EventArgs e)
at
System.Web.Http Application.Syn cEventExecution Step.System.Web .HttpApplicatio n.IExecutionSte p.Execute()
at System.Web.Http Application.Exe cuteStep(IExecu tionStep step,
Boolean& completedSynchr onously)