Since january, I switched to another laptop with almost the same specs.
So, I installed again virtualbox and then, I don't know why, but now the VM detected my virtualbox platform and it works, I can use dataiku DSS free edition without any problems.
I used default specs as declared while opening the OVA file as before, I guess that it could be a problem with virtualbox path installation or something related to.
For now, it's fixed but I don't have a clue about what was the root cause.
Thanks again for answering.