You can do it from the command line on Mac OS, but you need to be careful to image the correct disk as it’s possible to overwrite your hard drive if you make a mistake.
First download the image which will be an img.gz file, then double click it in the Finder to extract it to a .img file.
Open a Terminal window before inserting the SD card and run:
diskutil list
This will show you the drives you already have on the system - take note of their names in the left column (/dev/disk0 etc - you might have only one) and do not accidentally image to one of them. Now insert the SD card, wait a few seconds then run the same command and you should find one more device.
In my case this is /dev/disk2, and I can see that it’s an 8GB device. Now we need to unmount the disk so it’s not in use, but without actually ejecting the device completely, which can’t be done in the finder. If the device is partitioned you will see the partitions under the “identifier” column. On mine it shows disk2 and disk2s1, so:
diskutil umount /dev/disk2s1
(Do this for each disk2s1 disk2s2 and so on, but not for disk2)
Now you can image the file:
sudo dd if=OSMC_TGT_vero_20151027.img of=/dev/disk2
Replacing the filename with your image file and /dev/disk2 with the device name you determined earlier. If you make a mistake here you can wipe your hard drive.
This could take a few minutes and will come back to a command prompt when finished.
When it is finished eject the disk properly:
diskutil eject /dev/disk2
Again substituting the disk name you found earlier.
BTW to help us find the problem with the installer please provide the full installer log. Your extract is not sufficient to be of any use.