I've been bitten by the same 910 GO and TT Home backup bug that many others have apparently. I was actually directed to this site by TomTom Support US, since they indicated they are unable to help.
As many have done, I performed a backup of my 910 GO after first recieving it. I have used the unit for quite a while without issue. I recently was doing an update via Home when an error occured with a map update. I clicked on the link in Home and it sent me to a troubleshooting page (located in the UK).
I followed the steps verbatim, including the last one which stepped me through re-formatting the 910. After completing that and attempting to re-install my backed up maps to the GO I encountered errors. Now I have a GO with no maps.
I called support. They are working with me to get the maps restored, however they have indicated that they do not have the contents of the LoquendoTTS to provide, which as many of you have found does not get backed up by Home.
So, now even if they do manage to get my maps working, I will not have the TTS voices.
TomTom Support US suggested that I ask here to see if anyone could provide a link of offer to send via FTP, the files in the LoquendoTTS folder from a GO 910 backup. It seems ludicrous to me that TomTom doesn't have them to provide themselves, but whatever.
Anyone out there able to lend a helping hand?