Still not working
Thanks for helping. You were right i had DFP still installed (i thought i had remove it, sorry. Anyway it seems it wasnt the cause of the problem...)
I have deleted Wincache File, renamed Config Folder, uninstalled all extensions and re-installed the newest ones, taking care not to install DFPro with UE4 and Validation Toolkit with FormBuilder.
And it still does'nt work !! As soon as the Email is applied i get the error. I made a video record of what i do so can exactly know the process i follow i maybe see if i am doing something wrong.
Please have a look at UE4-headaches.html (FLV video).
There is no sound, it is self explanatory.
Attach is a screenshot of my actual extensions currently installed.
I have lost several days and will have to deliver the site to the client soon so i hope the solution is "close" ;-)