Thanks for your reply. I am just creating the new site. So I have installed the new - latest release of Moodle (zip) file. I could see the wiki and chat module in the Admin/mod of the Moodle settings itself. I have clicked the button to show the modules. But it is not showing anywhere.
So I have just tried to install wiki and chat into the mod directory of moodle. But it end up in the error. So what would be the problem. Hope you understood my problem.
If you want, I can show you the site: http://132.132.96.153/moodle2/moodle/
Regards,
Joseph