[TYPO3-project-formidable] newbie question

[Ismaël Bidau]

Hi,

i start today to try Formidable (1.1.0).

I read 
http://formidable.typo3.ug/tutorials/run-a-formidable-application-without-making-fe-plugin.html

I link the plugin with a xml file found here :
http://formidable.typo3.ug/tutorials/start-up-a-project-with-formidable.html

But in frontend, I've a bug message :
"'typo3conf/ext/ameos_formidable/pi2/locallang.php' is no TYPO3 language 
file)!"

What I missed ?

Thanks a lot.
I view the podcast and read some docs, formidable seams a really 
powerful and a clean way to make my FE forms.