Problem emailing web page

[paulhux174]

I'm trying to send several emails using the webpage by getting a string
copy of it using the RenderControl() function of System.Web.UI.Page.
I've added code below
Program logic is:
hide some buttons and labels and controls,
render page send email,
Then
hide other parts, show other parts,
render again (fails here with "A page can have only one
server-side Form tag."),
send email
Then
redo process again.

it looks like its appending the page onto the original copy of it.
I've put the render function (below) in a separate class.

Is there another way to do this? or a correct way?
Thanks in Advance

public static string RenderFormControl(System.Web.UI.Page page)
{
StringBuilder SB = new StringBuilder();
TextWriter SW = new StringWriter(SB);
HtmlTextWriter htmlTW = new HtmlTextWriter(SW);
System.Web.UI.Page copyofThisPage = page; // shouldn't need
as page should

// be a Value parameter

copyofThis.RenderControl(htmlTW);
string retVal = SB.ToString();
copyofThisPage.Dispose(); // Tried
return retVal;
}

public override void VerifyRenderingInServerForm(Control control)
{ }

public override bool EnableEventValidation
{ get
{ return false; }
set { base.EnableEventValidation = value; }
}