Test POST

I started to test upcoming api today. When I tried to to test following steps mentioned here http://upcoming.yahoo.com/help/w/API_POST_Method_Tips. it gives back the error message which is given below.


<?xml version="1.0" encoding="UTF-8"?>
<rsp stat="fail">
<error msg="Invalid authentication parameters" />
</rsp>
<!-- w4.up.re3.yahoo.com uncompressed/chunked Fri Jul 16 02:23:02 PDT 2010 -->

Please help.

Thanks
Srinadh