Re: Error: could not write bytes: Broken pipe
After logging in on the TTY prompt there are several alternatives: apt-get install; jockey-gtk or synaptic.
The first: is the only choice if the graphics screen is not accessible, yours is, so it is not essential:
Second will give you access to the same GUI as running System Settings>Additional Drivers, and it gives no indication of which version it will load, and maybe not only that but the name may be uninformative; eg: " NVIDIA binary Xorg driver, kernal module and VDPAU library"Thirdly: Will run the Synaptic Package Manager and you can choose which version to mark for installation, and select 'Apply'.
sudo apt-get update
sudo apt-get install nvidia-current-updates # the package name of the post-release version 295.49
When the Window opens, give it time to renew the index and display " Quick Filter " above the string box, then enter 'nvidia'.
I would recommend, if it shows, 'nvidia-current' version 304.43-0ubuntu1, rather than the 'nvidia-current-updates' version 295-49-0ubuntu0.2.
I have had the 'Broken Pipe' error messages, at log-in and shut down, ever since I installed 12.04 on the first day of its release. I have Posted about it but have had no response, nor found any info about its cause or effect. For me, at least, it seems to have no importance.
"Better Solutions may bring Worsened Problems": After Lao Tse, b. circa 405BC. a contemporary of Confucius, who died circa 600BC.
They did things differently in those days, apparently!!