I'm not sure if I follow you... anyway. Start with a fresh ume.ini file with the default options (lock_system_modes must be 1, do not use "monitor ntsc", leave "monitor generic_15").
Then check if everything works as expected from command line.
If this is the case, leave the ume.ini configuration as it is and focus on fixing the configuration of your frontend which must achieve the exact same results you're getting from command line, otherwise it's wrongly configured.