Unable to upload files

Attempting to upload files to the "Download Page" I get an error:
<Error>
<Code>MaxPostPreDataLengthExceeded</Code>
<Message>
Your POST request fields preceeding the upload file was too large.
</Message>
<MaxPostPreDataLengthBytes>20480</MaxPostPreDataLengthBytes>
<RequestId>367CF3CDAAC0B5B2</RequestId>
<HostId>
xBPWt7hS6EQYOq7gSbf1N2bY8EXEbqCXs/ExaXrpeG/G9k64GOfYyTKqFP5K+UFq
</HostId>
</Error>