OK. I did the emerge command and it did this:
sabayonx86 matt # emerge ndiswrapper
Calculating dependencies... done!
>>> Emerging (1 of 1) net-wireless/ndiswrapper-1.39 to /
>>> Downloading 'http://distfiles.gentoo.org/distfiles/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://distfiles.gentoo.org/distfiles/n ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving distfiles.gentoo.org... failed: Name or service not known.
>>> Downloading 'http://distro.ibiblio.org/pub/linux/distributions/gentoo/distfiles/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://distro.ibiblio.org/pub/linux/dis ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving distro.ibiblio.org... failed: Name or service not known.
>>> Downloading 'http://ovh.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://ovh.dl.sourceforge.net/sourcefor ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving ovh.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://jaist.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://jaist.dl.sourceforge.net/sourcef ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving jaist.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://mesh.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://mesh.dl.sourceforge.net/sourcefo ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving mesh.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://easynews.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://easynews.dl.sourceforge.net/sour ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving easynews.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://nchc.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://nchc.dl.sourceforge.net/sourcefo ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving nchc.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://kent.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://kent.dl.sourceforge.net/sourcefo ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving kent.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://switch.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://switch.dl.sourceforge.net/source ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving switch.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://osdn.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://osdn.dl.sourceforge.net/sourcefo ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving osdn.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://keihanna.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://keihanna.dl.sourceforge.net/sour ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving keihanna.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://heanet.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://heanet.dl.sourceforge.net/source ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving heanet.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://ufpr.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://ufpr.dl.sourceforge.net/sourcefo ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving ufpr.dl.sourceforge.net... failed: Name or service not known.
>>> Downloading 'http://surfnet.dl.sourceforge.net/sourceforge/ndiswrapper/ndiswrapper-1.39.tar.gz'
--12:07:57--
http://surfnet.dl.sourceforge.net/sourc ... .39.tar.gz => `/usr/portage/distfiles/ndiswrapper-1.39.tar.gz'
Resolving surfnet.dl.sourceforge.net... failed: Name or service not known.
!!! Couldn't download 'ndiswrapper-1.39.tar.gz'. Aborting.
So then I went and manually got ndiswrapper-1.39.tar.gz and placed it in /usr/portage/distfiles, then I did emerge again:
sabayonx86 matt # emerge ndiswrapper
Calculating dependencies... done!
>>> Emerging (1 of 1) net-wireless/ndiswrapper-1.39 to /
* ndiswrapper-1.39.tar.gz MD5

... [ ok ]
* ndiswrapper-1.39.tar.gz RMD160

... [ ok ]
* ndiswrapper-1.39.tar.gz SHA1

... [ ok ]
* ndiswrapper-1.39.tar.gz SHA256

... [ ok ]
* ndiswrapper-1.39.tar.gz size

... [ ok ]
* checking ebuild checksums

... [ ok ]
* checking auxfile checksums

... [ ok ]
* checking miscfile checksums

... [ ok ]
* checking ndiswrapper-1.39.tar.gz

... [ ok ]
* See
http://www.gentoo.org/doc/en/gentoo-kernel.xml for a list of supported kernels.
* Determining the location of the kernel source code
* Unable to find kernel sources at /usr/src/linux
* This package requires Linux sources.
* Please make sure that /usr/src/linux points at your running kernel,
* (or the kernel you wish to build against).
* Alternatively, set the KERNEL_DIR environment variable to the kernel sources location
!!! ERROR: net-wireless/ndiswrapper-1.39 failed.
Call stack:
ebuild.sh, line 1630: Called dyn_setup
ebuild.sh, line 702: Called qa_call 'pkg_setup'
ebuild.sh, line 38: Called pkg_setup
ndiswrapper-1.39.ebuild, line 33: Called linux-mod_pkg_setup
linux-mod.eclass, line 458: Called linux-info_pkg_setup
linux-info.eclass, line 554: Called die
!!! Unable to calculate Linux Kernel version
!!! If you need support, post the topmost build error, and the call stack if relevant.
!!! A complete build log is located at '/var/tmp/portage/net-wireless/ndiswrapper-1.39/temp/build.log'.
!!! This ebuild is from an overlay: '/usr/portage/local/layman/sabayon'
Im not sure if it worked or not.