By default under IIS there is a limitation on asp uploads of 200kb.
To resolve this problem:
1. Open the file C:WindowsSystem32inetsvrmetabase.xml in Notepad.
2. Find the entry AspMaxquestEntityAllowed and increase the value, which is given in bytes. For example, setting it to 50000000 means 50 million bytes (approx 50MB).
3. Save your changes to metabase.xml.
4. Restart IIS.