KeyError : KeyNotFound

I am running a knife ec restore command and I see the below error. Anyone knows why this could be happening

DEBUG: No chefignore file found at /home/xyzuser/server_backup/organizations/xyz/chefignore no files will be ignored
/opt/opscode/embedded/lib/ruby/gems/1.9.1/gems/knife-ec-backup-2.0.1/lib/chef/tsorter.rb:17:in fetch': key not found: "000000000000f5e4fe07d6a9c5953a09" (KeyError) from /opt/opscode/embedded/lib/ruby/gems/1.9.1/gems/knife-ec-backup-2.0.1/lib/chef/tsorter.rb:17:intsort_each_child'
from /opt/opscode/embedded/lib/ruby/1.9.1/tsort.rb:203:in each_strongly_connected_component_from' from /opt/opscode/embedded/lib/ruby/1.9.1/tsort.rb:209:inblock in each_strongly_connected_component_from'
from /opt/opscode/embedded/lib/ruby/gems/1.9.1/gems/knife-ec-backup-2.0.1/lib/chef/tsorter.rb:17:in each' from /opt/opscode/embedded/lib/ruby/gems/1.9.1/gems/knife-ec-backup-2.0.1/lib/chef/tsorter.rb:17:intsort_each_child'
from /opt/opscode/embedded/lib/ruby/1.9.1/tsort.rb:203:in each_strongly_connected_component_from' from /opt/opscode/embedded/lib/ruby/1.9.1/tsort.rb:182:inblock in each_strongly_connected_component'
from /opt/opscode/embedded/lib/ruby/gems/1.9.1/gems/knife-ec-backup-2.0.1/lib/chef/tsorter.rb:13:in each_key' from /opt/opscode/embedded/lib/ruby/gems/1.9.1/gems/knife-ec-backup-2.0.1/lib/chef/tsorter.rb:13:intsort_each_node'
from /opt/opscode/embedded/lib/ruby/1.9.1/tsort.rb:180:in each_strongly_connected_component' from /opt/opscode/embedded/lib/ruby/1.9.1/tsort.rb:148:intsort_each'
from /opt/opscode/embedded/lib/ruby/1.9.1/tsort.rb:135:in `tsort'

Reproduce the failure with the knife ec restore command, then inspect lib/chef/tsorter.rb at line 17 and the surrounding restore path. Trace why the referenced key is absent during topological sorting; done means the restore no longer raises this KeyError for the reported backup and the behavior is covered by an appropriate regression test.