[TYPO3-templavoila] "ERROR: Content Element type "templavoila_pi1" has no rendering definition!"

[Stefan Collon]

Hello all,
i updated Typo from 4.1 to 4.4.0
all extensions are the same, and templavoila is installed properly 
(version 1.4.4)
i also configured it in the template setup with:

page.10 = USER
page.10.userFunc = tx_templavoila_pi1->main_page

i cleared all caches and in the backend everything shows up right.
i can see my own templavoila TOs and DS, i can create new ones in my 
pages and update/delete old ones.

But when it comes to frontend view, no tv-object shows up.
Instead i get multiple errors saying:

"ERROR: Content Element type "templavoila_pi1" has no rendering definition!"

What's crazy is, that all of my page templates, i created as DS and TOs, 
function perfectly.

Could anyone imagine what's wrong here?

regards,
Stefan