I tested DBeaver version under Windows XP and Windows 7 in VirtualBox + the last java.com version (JRE8update25 32 and 64 bits).
If I install Dbeaver without JRE included in the installer package, I've got this error under Windows XP and under Windows 7 when I start DBeaver :
"Failed to find a Main Class in "C:\Program Files\DBeaver\plugins\org.eclipse.equinox.launcher_1.3.0.v20140415-2008.pack"
If I install Dbeaver with JRE included in the installer package, I've got no error, under Windows XP and under Windows 7 when I start DBeaver but nothing appears, DBeaver doesn't start.