Problemer med upload via "Chili.Upload.1"

Jeg synes jeg holder mig til de eksempler jeg har kunnet finde, men alligevel får jeg følgende fejl:

Error Type:
Chili.Upload.1 (0x80004005)
Form does not contain a file element.


Her er koden:
<form action="?upload=nu" enctype="multipart/form-data" method="post">
<input type="file" name="file" class="knapper">
<input type="submit" value="Upload fil" class="knapper">
</form>


<% if request.querystring("upload")="nu" then
Response.Expires = 0
Set fbase = Server.CreateObject("Chili.Upload.1")
fbase.SizeLimit = 500000
fbase.SaveToFile(Server.mapPath("/"))
<% end if%>