Anand, sadly there is something wrong with the module which generates the search engine friendly URLs and that causes the problem. During the test installation we never meet with this problem, but as you might read it is a common problem. If the seo friendly URLs are not as important for you i would like to ask you to set the $mosConfig_sef value at the configuration file to zero instead of the 1. This will solve the problem. If you want me to fix this at your site please fill
this form and i wil have a look at your site. In the next couple of days i will upload a newer package that will solve this problem and make possible to use the sef module.
Thank you for understanding.