[ASP.NET]Error: A potentially dangerous Request.QueryString value was detected

Error Message

"A potentially dangerous Request.QueryString value was detected from the client " 

Cause

.NET Framework 1.1 is installed on an application that was developed using .NET 1.0. .NET 1.1 uses a higher security setting by default, so a security message that 1.0 users don't see is visable.

Solution or Workaround

Disable these error messages by lowering the security settings. Set validateRequest=false in the Page directive of the *.aspx page that displayed the error. This will turn off request validation for that page only.

The first line should be similar to this in VB.NET:

<%@ Page Language="vb" AutoEventWireup="false" Codebehind="WebForm1.aspx.vb" Inherits="TestWebGUI.WebForm1" validateRequest=false%> 

or

<configuration>
   <system.web>
      <pages validateRequest="false" />
   </system.web>
</configuration>

Other References: Request Validation - Preventing Script Attacks