I am migrating Umbraco from one server to another. I have copied the files and exported/imported the database. But when I browse to the migrated site I get this message.

Object reference not set to an instance of an object.

Line 9:

<script type="text/javascript">
Line 10:     function startUmbraco() {
Line 11:       window.open('umbraco.aspx', 'u&lt;%=Request.ServerVariables["SERVER_NAME"].Replace(".","").Replace("-","")%>', 'height=600,width:850,scrollbars=yes,resizable=yes,top=0,left=0,status=yes');
Line 12:     }
Line 13:   </script>

[NullReferenceException: Object reference not set to an instance of an object.] umbraco.presentation.urlRewriter.UrlRewriterFormWriter.WriteAttribute(String name, String value, Boolean fEncode) +421 System.Web.UI.HtmlControls.HtmlForm.RenderAttributes(HtmlTextWriter writer) +740 System.Web.UI.HtmlControls.HtmlControl.RenderBeginTag(HtmlTextWriter writer) +41 System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +20 System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output) +53 umbraco.presentation.urlRewriter.FormRewriterControlAdapter.Render(HtmlTextWriter writer) +49 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +106 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer) +40 ASP.umbracodefaultaspx.Rendercontrol1(HtmlTextWriter _w, Control parameterContainer) in \n5200-2\iis7www\s\a\samex.co.nz\www\umbraco\Default.aspx:11 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +268 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8 System.Web.UI.Page.Render(HtmlTextWriter writer) +29 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +57 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1386

I was hoping someone can point me where to troubleshoot.

Scott