VS 2012 SpiraTeam Project Explorer throwing error and won't start

  <entry>

    <record>1479</record>

    <time>2014/10/30 03:34:50.695</time>

    <type>Error</type>

    <source>VisualStudio</source>

    <description>End package load [Inflectra.SpiraTest.IDEIntegration.VisualStudio2012.SpiraExplorerPackage, SpiraExplorer, Version=4.1.0.0, Culture=neutral, PublicKeyToken=d918ac98f0eb7a44]</description>

    <guid>{6FDDDEA3-588B-4FE1-ACB7-9C5B03BCCBAD}</guid>

    <hr>80004005 - E_FAIL</hr>

    <errorinfo>Could not load file or assembly 'Microsoft.VisualStudio.Shell.10.0, Version=12.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.</errorinfo>

  </entry>