This is really a mess... my site loss all the configuration for mobile templates ands such. "The Incorrect usage of Mobile Joomla" ugly message appers and there's nothing left to do.
Maybe you're now having this huge problem like me...

First: I recovered my website just by restoing form backup my joomla mysql database.

Important: If you try to find/query for "mobile" on your mysql database, you wont a find anything, so,... restoring the whole database will be better, as a time saver solution.

Second: Don't try to reinstall the Mobil Joomla extension. That just make you loss some few minutes more and make your boss loose his patience. It doesn't make any difference.

People from Mobile Joomla: Include some feature to restore original values to something that actually works.

Third: Do NOT ever change the default page where Mobile Joomla will load in mobile devices. That will make you crash your site and make yourself fired and later on hired again when you restore your joomla site from backup (mysql database only may also work)

If I figure out how to uninstall Mobile Joomla forever and ever, I'll post again... please join me at www.deletingmobilejoomla.org for more information!

Thanks for reading!

I create subdomain at m.indoposting.com, but I only get message"Index of / cgi-bin". What should I do, and what's wrong with me. Should I redirect my subdomain to my homepage?

indoposting, you created separate subdomain, but it's necessary to create alias to main domain, or change subdomain DocumentRoot to be the same as main domain (so that they share the same directory on the server).