Videre med FSO -problemer

Meningen er at den skal skifte til billed "1.gif" så "2.gif" osv. osv afhængig af hvor mange bileder der findes i mappen:

<%
set fso = createobject("scripting.filesystemobject")
SubFolders = fso.GetFolder(server.mappath("GFX/PICS")).Files.Count


if Request.Querystring("C") > SubFolders then %>
    ss
<%
else
    if Request.Querystring("C") = "" then
        C = "1"
    else
        C = Request.Querystring("C")
    end if

    %>
    <center>
    <br><img src="gfx/pics/<% = C %>.gif" width="400" height="266" style="border: #000000 1px solid;"><br>
    <a href="default.asp?mode=pics&C=
    <% Response.Write C-1 %>">
    <img src="gfx/back.gif" border="0"></a>


    &nbsp;<img src="gfx/back-next.gif" border="0">&nbsp;<a href="default.asp?mode=pics&C=
    <% Response.Write C+1 %>
    "><img src="gfx/next.gif" border="0"></a>

<% end if %>

??