Do not install 2506143 (optional WMF 3.0 patch) on your SBS 2011 - THE OFFICIAL BLOG OF THE SBS DIVA:
http://msmvps.com/blogs/bradley/archive/2012/12/12/do-not-install-2506143-optional-wmf-3-0-patch-on-your-sbs-2011.aspx
http://msmvps.com/blogs/bradley/archive/2012/12/12/do-not-install-2506143-optional-wmf-3-0-patch-on-your-sbs-2011.aspx