Sudden error using web developer 2008 express

[tibor]

Hi all

I have a login page that calls a simple stored proc to process the user and password against a table. It was working perfectly fine last night and now suddenly i receive this message in regards to the password field:

[InvalidCastException: Failed to convert parameter value from a WindowsPrincipal to a String.]

the parameter is declared as:

Sql.Parameters.Add("@_iPassword", SqlDbType.VarChar, 40)
        Sql.Parameters("@_iPassword").Value = txtPassword.Text

What would suddenly cause a perfectly working call to this procedure to fail?

Thanks

[jmcilhinney]

Are you absolutely sure that that is where the exception is thrown? I doubt that it actually is.