type mismatch

These are the values I am sending to the gisdispatcher.asp


response.redirect ("bmpcon2.asp?userid=1&topleftx=&Lon1&&toplefty=&Lat1&&brightx=&Lon2&&brighty=&Lat2&")



<SCRIPT LANGUAGE="VBScript" RUNAT="Server">

Const SESN_GIS = "GIS_SESSION"


Function GISDispatcher_RequestMap(ByVal TheId,ByVal topleftX,ByVal topleftY,ByVal brightx,ByVal brighty,ByVal msh,ByVal msw)
'On Error Resume Next
GISDispatcher_RequestMap=Session(SESN_GIS).RequestMap(TheId,topleftX,topleftY,brightx,brighty,msh,ms w)
End Function


Function GISDispatcher_RequestVectorMap(ByVal TheId,ByVal topleftX,ByVal topleftY,ByVal brightx,ByVal brighty)
'On Error Resume Next
GISDispatcher_RequestVectorMap=Session(SESN_GIS).RequestVectorMap(TheId,topleftX,topleftY,brightx,br ighty)
End Function


</SCRIPT>




<font face="Arial" size=2>
<p>Microsoft VBScript runtime </font> <font face="Arial" size=2>error '800a000d'</font>
<p>
<font face="Arial" size=2>Type mismatch: 'Session(...).RequestMap'</font>
<p>
<font face="Arial" size=2>/yeomanlocal/GisDispatcher.asp</font><font face="Arial" size=2>, line 8</font>


This is the error I am getting, please can someone advise to me to resolving this problem, I having a feeling that it is due to the values that are being passed to the gisdispatcher asp?

Can anyone looking at the code, let me know if this is the problem?

I do not have enough knowledge of asp to know all the error
problem - messages.