Invaild Viewstate errors

v1.11
We appear to get error conditions raised when (some?) external (prospective) clients access our site. Testing ourselves doesn't throw up anything.
Whilst these clients have not reported any problems they have only looked at a few pages, presumably seen errors and left without reporting anything.
The page is always ScriptResource.axd but the parameter varies.

Any ideas would be welcome!

Log type:  Unknown  
Severity:  11  
Message:  Invalid viewstate.  
Exception:  System.Web.HttpException: Invalid viewstate. at System.Web.UI.Page.DecryptStringWithIV(String s, IVType ivType) at System.Web.UI.Page.DecryptString(String s) at System.Web.Handlers.ScriptResourceHandler.DecryptParameter(NameValueCollection queryString) at System.Web.Handlers.ScriptResourceHandler.ProcessRequestInternal(HttpResponse response, NameValueCollection queryString, VirtualFileReader fileReader) at System.Web.Handlers.ScriptResourceHandler.ProcessRequest(HttpContext context) at System.Web.Handlers.ScriptResourceHandler.System.Web.IHttpHandler.ProcessRequest(HttpContext context) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)  
IP address:  xx.155.236.xxx  
Customer:  
Page URL:  http://shop.paws4pets.net/ScriptResource.axd?d=BJ1INckQc2NIzWB2nDcJcYstkl8SHeN_hPVQXw6rkFs-bA8jyTLcc  
Created on:  6/17/2009 11:50:15 AM  

The server event log itself shows:-
(The parameter on this event log entry is different - the other entry has the same parameter as above)
Event Type:  Warning
Event Source:  ASP.NET 2.0.50727.0
Event Category:  Web Event
Event ID:  1309
Date:    17/06/2009
Time:    11:49:18
User:    N/A
Computer:  SUN
Description:
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 17/06/2009 11:49:18
Event time (UTC): 17/06/2009 10:49:18
Event ID: 0fa46f8a2a80404cbb6798a0ae289674
Event sequence: 40
Event occurrence: 1
Event detail code: 0

Application information:
    Application domain: /LM/W3SVC/413351422/Root-2-128896816362044982
    Trust level: Full
    Application Virtual Path: /
    Application Path: C:\Inetpub\nopCommerce\
    Machine name: SUN

Process information:
    Process ID: 3348
    Process name: w3wp.exe
    Account name: NT AUTHORITY\NETWORK SERVICE

Exception information:
    Exception type: HttpException
    Exception message: Invalid viewstate.

Request information:
    Request URL: http://shop.paws4pets.net/ScriptResource.axd?d=BJ1I=
    Request path: /ScriptResource.axd
    User host address: xxx.155.236.xxx
    User:  
    Is authenticated: False
    Authentication Type:  
    Thread account name: NT AUTHORITY\NETWORK SERVICE

Thread information:
    Thread ID: 1
    Thread account name: NT AUTHORITY\NETWORK SERVICE
    Is impersonating: False
    Stack trace:    at System.Web.UI.Page.DecryptStringWithIV(String s, IVType ivType)
   at System.Web.UI.Page.DecryptString(String s)
   at System.Web.Handlers.ScriptResourceHandler.DecryptParameter(NameValueCollection queryString)
   at System.Web.Handlers.ScriptResourceHandler.ProcessRequestInternal(HttpResponse response, NameValueCollection queryString, VirtualFileReader fileReader)
   at System.Web.Handlers.ScriptResourceHandler.ProcessRequest(HttpContext context)
   at System.Web.Handlers.ScriptResourceHandler.System.Web.IHttpHandler.ProcessRequest(HttpContext context)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)


Custom event details:

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

I don't see any replies here, but did you hear anything on this?

We are getting a lot of viewstate errors as well. Our application is installed on GoDaddy. I'm using a machineKey in the web.config which fixed similar errors, but we still get these rather frequently. I don't have access to the event log on GoDaddy. Is it because the the viewstate expires or something?

I am also getting this same error and not using GoDaddy , so i don't think that GoDaddy is causing this error, there must be something else

is there anyone who was able to solve this issue ?