As I see you have solved your problem. You can mark your own message as solution to the thread for the rest of the UT community.

>All,
>
>It looks like this was one of those subtle 'null' errors. Since I have changed the following code from
>

>if(Session["USERID"] == null)
>{
>    Response.Redirect("Logon.aspx?ReturnTo=" + PageName + ".aspx");
>}
>

>
>to
>
>

>if(common.IsNull(Session["USERID"]))
>{
>    Response.Redirect("Logon.aspx?ReturnTo=" + PageName + ".aspx");
>}
>

>
>My spurious redirects have disappeared. It seems a little weird to me - sometimes the compiler warns you you cannot compare to null, other times it lets the comparision slide right on by.
>
>Thanks to everyoen for the suggestions - just another part of the learning curve.
>
>Doug