Did not get what is this page about, no impression about site's mission. It it is a social network for students - then make it clear. At least I had no temptation to think about visiting such site for a second time. Registration, privacy, login - I have no use of them if nothing is explained on the first page (unless you are Facebook/Gmail...).
Black background+dark blue button with dark text --> bad decision. Hard to read.
Second image: header is not too good, in my opinion. It was hard for me to fing embossed "UGT" at the header. As I am not professional, it is hard to decide whether light green on a blue background is bad. For me, it does not fit.
As for Facebook (academic FB?) clone - more light colours, more interaction, more readibility and more explanations what this website is for.