Error in including ploneorg.core in buildout.cfg eggs

I am working on developing add-ons for plone.org as part of GSoC. I'd like to base my development on ploneorg.core to better understand it. So, I tried including ploneorg.core (from https://github.com/plone/ploneorg.core ) in the buildout.cfg eggs of the local Plone 5.0.7 setup. It resulted in the following error on running bin/buildout :

Getting required 'ploneorg.theme'
  required by ploneorg.core 1.0a1.
We have no distributions for ploneorg.theme that satisfies 'ploneorg.theme'.
Couldn't find index page for 'ploneorg.theme' (maybe misspelled?)
Getting distribution for 'ploneorg.theme'.
Couldn't find index page for 'ploneorg.theme' (maybe misspelled?)
While:
  Updating instance.
  Getting distribution for 'ploneorg.theme'.
Error: Couldn't find a distribution for 'ploneorg.theme'.

what might be wrong?

If you look at the buildout here: https://github.com/plone/ploneorg.core/blob/master/buildout.cfg

you'll notice some packages configured to be used as checkouts from source.

This particular error is because ploneorg.theme does not seem to be a released package and must be installed from source.

In the buildout file that you specified, ploneorg.theme has already been listed in auto-checkout and has ploneorg.theme = git git://github.com/plone/ploneorg.theme.git pushurl=git@github.com:plone/ploneorg.theme.git
mentioned under [sources].
Does it not mean that it is already being installed from source?

Yes

@pavithirakc did you get it working?

No, I am not able to understand why it gives 'Couldn't find a distribution for 'ploneorg.theme'' error , when it is being checked-out from source.

I showed an example of a buildout that is checking it out from source. As far as I can tell, your buildout IS NOT checking out from source. If it were, you wouldn't get this error.

As @vangheem says, that error proves that your buildout.cfg (or something it includes or extends) is incorrectly telling buildout to fetch the egg from pypi.python.org but isn't finding it. (That's exactly what that error means).

Look for and delete any version pin for ploneorg.theme in any of your *.cfg files.

Or please post your buildout.cfg and other *.cfg files here.