I am assuming that since you have the _V version, that you have a WD TV Live. If that is true, go to this web page and download the 1.04.31_V firmware. Then follow the directions on that page to install it.
Basically, you download the file, unzip it, put the .BIN, .VER, and .FFF files in the root directory of a portable USB drive. Then plug the USB drive into the WD TV Live and go to the Settings screen. You should see the new firmware found icon.
wizardthering, There are 2 different firmwares, one for the live, and one for the Live Plus, as TonyPh12345 said, the Live firmware ends with _V, and the Live Plus firmware ends with _B. You have to use the correct version for your device. If you try to use the wrong version it will not install. The link that I gave you above was for the WD Live. If you have a Live Plus, then you have to use this version:
If you are using the correct version of the firmware and it still won’t install, you can try one other thing. After you un-zip the firmware file, use a regular text editor, like Notepad, to open the .ver file. In there you will see a line that says: VERSION=‘1.05.04_V’. Change the version number in the file to 2.05.04_V, then try to install from the USB drive. The firmware will not install unless it thinks that it is newer, and this will trick the installer into thinking that the firmware is a newer version.