Eclipse IDE installation fails because it can’t the find mars repository

There are a few Eclipse bugs related to this. All the threads seem to be resolved by deleting the $HOME/.eclipse/org.eclipse.oomph.p2/cache directory.

bugs.eclipse.org/bugs/show_bug.cgi?id=471528#c7

bugs.eclipse.org/bugs/show_bug.cgi?id=470900

eclipse.1072660.n5.nabble.com/No-repository-found-exception-td175271.html

If this has made its way back into the executable file, you may need to open a new bug.

In the meantime, you may need to install the previous version, Luna, instead though I would try installing the 32-bit version of Mars first.