@dimdam you're kidding? Why do you need this useless plugin?
You can implement tracking via html-module:

1. Create new "Custom HTML" module
2. Toggle off html editor
3. Insert tracking code from piwik
4. On the "Options" tab uncheck "Prepare Content"(set to No)
5. Select the module position(e.g. Footer)
6. Save & Close
7. ...
8. Profit

@Globulopolis tried what you said but nothing changed. Still getting the " No analytics data has been tracked for this website yet. Please set up the JavaScript tracking code on your website and refresh the page." message. Thank you for your time though

@dimdam which period you want to see in reports? What do you see in "Visitor live"?

@Globulopolis i cant see anything. When i select the Joomla site ,the only thing i can see is the message i wrote on my previous comment, and "No data has been recorded yet"

Minimum period for reports - full day.

@Globulopolis just to be clear (because i have another site and piwik started showing reports from the very first second),you are saying that i have to wait 24 hours to bypass this: http://i.imgur.com/pZ1rOpk.png ?

@dimdam this two sites on the same piwik instance or different?

Just for test you can check the #_log_visit table and look for last records for selected idSite. If no records for selected idSite when tracking code not working.

@dimdam you don't need to wait 24 hours, the screen will go away as soon as even one request is tracked in piwik. There are many reasons why you may not see data tracked in Piwik, check out this FAQ for more info: http://piwik.org/faq/troubleshooting/faq_58/

if you experience a particular bug feel free to create an issue