I had this error, and I wrote down what I did at the time for future reference:
The first attempt on this install didn't work as I mistakenly chose GPT not DOS for the disk after having previously totally wiped it with badblocks -ws and this GPT setting was then retained causing subsequent installation attempts to fail as there was no option to change it in cfdisks.
GPT isn't needed for older BIOS installs, it's for TB sized disks and it needs an extra partition for the gpt table that I hadn't created. It could have worked then but would have wasted a little disk space for no benefit to me that I know of.
Error! Failed to install Grub
Check /dev/tty8 for errors
(Ctrl Alt F8 to see, Ctrl Alt F7 - could be F1 for a terminal install - to return to the original tty)
I ran void-installer again, but there was no install menu option to switch from gpt to dos after the selection was made. I deleted the partitions made earlier and shut down to try again later after more online research.
So, now to install and correct my earlier error:
Boot CD using RAM option - I had 1GB RAM installed.
At start of XFCE desktop select default config. Then there's a terminal icon on the bottom panel.
Follow the onscreen instructions and make the usual bunch of installer setup selections - keyboard, locale, timezone etc.
Didn't bother setting up a network connection as I'm installing from the CD image.
Go through menus, cfdisk still says it's a GPT disk and won't offer to change it, when unset there had been a choice in the menu. So I used the interactive fdisk program from the live image:
shift ctrl t - open a new tab in XFCE terminal.
$ sudo fdisk /dev/sda
m (for help)
That changed it to DOS.
Partition drive as required:
/dev/sda1 primary bootable 26.9G 83 Linux
/dev/sda2 primary not bootable 1.1G 82 Linux swap / Solaris
Write to disk, type yes. Quit.
/dev/sda1 mount / fs = ext4
/dev/sda2 linux swap
Back to go back to main menu
Select install, about 5 minutes later it had installed Void successfully this time.
Perhaps your error is different though. On my latest install which I'm using now, I am using BTRFS not EXT4.