Server Error in '/' Application. Key cannot be null. Parameter name: key
<p>Sometimes I'll come back to the problem of making the report,i use this for report in stimulsoft:</p>

<pre><code>Key cannot be null.
Parameter name: key
Description: An unhandled exception occurred during the execution of the current web  
request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ArgumentNullException: Key cannot be null.
Parameter name: key

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[ArgumentNullException: Key cannot be null.
Parameter name: key]
System.Collections.Specialized.HybridDictionary.get_Item(Object key) +6238250
System.Web.Security.RolePrincipal.IsInRole(String role) +231
System.Web.Configuration.AuthorizationRule.IsTheUserInAnyRole(StringCollection roles, IPrincipal principal) +132
System.Web.Configuration.AuthorizationRule.IsUserAllowed(IPrincipal user, String verb) +264
System.Web.Configuration.AuthorizationRuleCollection.IsUserAllowed(IPrincipal user, String verb) +201
System.Web.Security.UrlAuthorizationModule.OnEnter(Object source, EventArgs eventArgs) +9025485
System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +148
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&amp; completedSynchronously) +75
</code></pre>

<p>How do we fix it?</p>

<p>tnx</p>
