[SOLVED in v3.0.8+] Date error in Item form after updating to Joomla 3.4.4

can you re-download file and retry ?

I tried on the same 2 sites. And the install went well, no warning and no error.
But on one of them, I get
Fatal error: Call to a member function asXML() on a non-object in /components/com_flexicontent/classes/flexicontent.helper.php on line 4391
if trying to edit or create new item

Try clearing backend and frontend joomla cache

I tried but i still have the same issue.
I completely emptied the cache, cookies... everything. And the errors remains.

Could it be that I upgraded form FC 2.2.0 Stable to 3.0.8 directly?

It's very strange.
I did a fresh install of Joomla and flexicontent. I checked to be sure i had the same extension installed. And actually removed as much unnecessary ones.
I then brought the DB from the original site to the one thinking that it may have been an actually issue with some php files . But the error is still there.
Fatal error: Call to a member function asXML() on a non-object in /components/com_flexicontent/classes/flexicontent.helper.php on line 4391

Which makes me think that it's actually not related to a php file.

My problem is that I did a newbie mistake by upgrading with out a latest backup. Since I've upgraded a few site before without any problem, I just went a head. Damn rookie mistake !!!