EDIT: in log he complains about "-syncmode" parameter which doesn't exist, if i change "-syncmode=fast" to "--fast" in "Settings" of client he doesn't save it - where is the config file for this parameter to edit? i think thats the issue he doesn't start gdbix.exe with dbixwall.exe together

You are correct, sir! The syncmode parameter doesnt exist. When trying to run the gdbix deamon from a command line with the --syncmode=fast argument it will fail to start since an incorrect argument is passed. The right argument should be --fast as you suggested.
The thing is that you cant change this argument within the new v2.0 software, because the setting never gets saved. So on a restart the software will always try to run gdbix with the --syncmode=fast argument. Who the hell tested this software??? Perhaps an outdated version of gdbix was supplied with the new v2.0 software?