From http://techlogbook.wordpress.com/2014/08/19/installing-metasploit-on-xubuntu-14-04/
$ msfconsole
/usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in require': cannot load such file -- /usr/local/bin/config/boot (LoadError)
from /usr/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in
require'
from /usr/local/bin/msfconsole:23:in `'
What I did was to edit /usr/local/bin/msfconsole line 23, and replace that line with:
require File.expand_path('/usr/local/share/metasploit-framework/config/boot.rb', __FILE__)
Make sure that the path for config/boot.rb is correct for your system.
Now, when I run msfconsole again, it gives me some warning of missing permission to write some log file.
Rails Error: Unable to access log file. Please ensure that /usr/local/share/metasploit-framework/log/production.log exists and is chmod 0666. The log level has been raised to WARN and the output directed to STDERR until the problem is fixed.
So I need to create the directory and make sure it is accessible.
$ cd /usr/local/share/metasploit-framework/
$ mkdir log
$ chmod 777 log
Now, I can run msfconsole. Before reaching the prompt, however, I got the following warning:
[-] WARNING! The following modules could not be loaded!
[-] /usr/local/share/metasploit-framework/modules/auxiliary/scanner/smb/smb_login.rb: LoadError cannot load such file -- robots`
Maybe that can help you get started