On 2014-02-11, Microsoft released bulletin MS14-009 – Important. Vulnerability CVE2014-0257 is among the list of fixes. This relates to an elevation of privileges through use of reflection to execute code normally inaccessible to the caller. Part of the solution involves disabling reflection over COM interfaces. This resulted in a family of patches for all .NET Framework and Windows combinations. You can view the list through the link above.
Microsoft released a follow-up KB2934830 to address problems with running macros through Visual Studio. You will need to edit one or more of the following files as an administrator:
C:\Program Files (x86)\Common Files\Microsoft Shared\VSA\8.0\VsaEnv\Vsmsvr.exe.config
C:\Program Files (x86)\Common Files\Microsoft Shared\VSA\9.0\VsaEnv\Vsmsvr.exe.config
C:\Program Files (x86)\Common Files\Microsoft Shared\VSA\9.0\VsaEnv\Vsmsvr10.exe.config
Add this under the runtime section. runtime should already exist:
This should make macros execute as expected.