what is the best way to report possible errors (content and translation) inside the eKit ?
I don't have an easy answer.
The eKit was porbably sold through Oracle University .... your contract is probably with them .... and you could try live chat at education.oracle.com but quite frankly I'm not sure I fancy your chances.
It is also likely some paperwork will be sent by Oracle for the purchase.
It is now the weekend.
I'd suggest raising a SR at http://education.oracle.com/pls/eval-eddap-dcd/OU_SUPPORT_OCP.home?p_source=OCP anyway.
Add the SR# to this thread.
The SR will take 4/5 days to come through .... but the certification programme manager (Brandye) often (voluntarilty) checks and advises here (but certainly not at weekends ....(and she is recovering from eating Haggis or something ( ;-) [ was Burns night is scotland, and Haggis is illegal in America ] ) .... she will do better if she has an SR number to reference.