Hi Calin,
How do you start the db studio? Please open a command prompt as administrator (right click -> run as adminstrator) and then go to the directory where dbstudio.exe located and then
dbstudio.exe -vm "C:\Program Files\Java\jre1.8.0_45\bin"
Certainly you have to adjust the path so that it is the bin directory of the java installation on your computer.
Cheers,
Péter