HTTP Status 500 - Null input expection while redir

When i access my fedlet it redirects me to adfs login screen wherein I enter my credential and then from that login page I am redirect to the fedlet application page where it shows "HTTP Status 500 - Null input " exception. I am not getting what must be going wrong. Please can anyone help me with the solution.

am also enclosing the decoded response sent back to help : " http://aaa.domain.com/adfs/services/trust CN=sso_te, OU=IT, O=comapnyname 1352204053 fHQDdZB2QYtpvmkjA+k+z2xDcIM8iE7esA9qpeiSvDsiPnfw5QoVKFis16wkA0XHIeZA4rLn0OWZ2gkAkx3GAVCCQe1MDpET/VGg1YcLs60YD3gu7zH2KZHERXwamxR4yHpT7Sf4Gh/Wwl98kJ644SZAwy2sC7xsqJKtQ+EpPFUZVs9Ii3pRfRscXIVysHqmMPuEdtCNQg0CkYNLNYiiU59Ki2i/CP0TJDI08uZ0r0ukqFNbatRpZ4ABTTum0/XLVzInvVwuRJfdrM/+cY4h7X5AG5mVDWbjZiqdACvv65vBHPW+CJsW5hP9y5O54/ICKvLOhCzXAFcMV+nGwmvLiA== pCTZd0kNSw6DrM/R/eAKNGnL2sctIjeSgxC9dE75nRsgHudTZOhWslACex4vWYnJS4HN2Vw6YGJdw/vgid4CimY/VCC1YNKokru7eVXX4pRfQ3T95S8wP7UeBapblMqVPzvdNBpnQPy9MII/ZYFcauY6m+2AETJ0V0VmZI75dmsONT+1CsVVpwQm5x3+lRfchzV8mOO/Ynj3hQYQ4ubX+vYuy6hdQrJx3GG5pIv "

Thanks a lot if anyone can help me.

Run in Firefox - clear all cookies.

Start up the SAML tracer.

If you run in FireFox with the SAML tracer enabled, when you redirect to AFDS you should see a message in the SAML tracer marked with an orange SAML button. If you click on the SAML tab, the message with be a:

<samlp:AuthnRequest ...

The response will be a:

<samlp:Response

and it will contain something like:

<AttributeStatement>
            <Attribute Name="http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name">
                <AttributeValue>Joe Bloggs</AttributeValue>
            </Attribute>
            <Attribute Name="http://schemas.xmlsoap.org/ws/2005/05/identity/claims/emailaddress">
                <AttributeValue>a@company.com</AttributeValue>
            </Attribute>
</AttributeStatement>

which matches the claims you configured for the RP in ADFS.

Do you see anything like this?

I have no idea what your message represents.