I wanted to install the 7.5.7 version into a new directory (no upgrade from 7.5.6.p2) and then import the sql database (like from 6.5 to 7.x) to that new installation.
Is this possible or shouldnt I do that like you said ?
That's not a good method to upgrade... You're skipping any possible db changes by doing this...
You should really REALLY follow an
Upgrade Guide.