If you use a http – upload script that uses byte – streaming on IIS, there is a problem with large fileuploads.

IIS 6 on Windows 2003 Server prevents the upload of files larger than 200 Kb by default – if you use a http-upload via ASP based on byte-streaming (like “Pure ASPUpload”), you will recieve a 403 error response from the server if you try to upload files larger than 200 Kb.

For IIS6.0 users, the AspMaxRequestEntityAllowed property specifies the maximum number of bytes allowed in the entity body of an ASP request. If a Content-Length header is present and specifies an amount of data greater than the value of AspMaxRequestEntityAllowed, IIS returns a 403 error response.

This property is related in function to MaxRequestEntityAllowed, but is specific to ASP request. Whereas you might set the MaxRequestEntityAllowed property to 1 MB at the general World Wide Web Publishing Service (WWW Service) level, you may choose to set AspMaxRequestEntityAllowed to a lower value, if you know that your specific ASP applications handle a smaller amount of data.
Solution

Open your metabase.XML which is located in c:\Windows\System32\Inetsrv find the line “AspMaxRequestEntityAllowed” and change it to a higher value (default value is set to 204800 – 200 Kb).

Be sure to first stop IIS service, edit metabase.XML, save the changes and restart IIS.