When you're planning on configuring Fax Services on Server 2008, 2008R2, and their SBS counterparts (SBS 2008 and SBS 2011), it's strongly recommended to install these hotfixes as they resolve intermittent crashes with the Fax Server services.

• http://support.microsoft.com/kb/2302075
  
• http://support.microsoft.com/kb/973640
  

It's highly recommended to install both hotfixes. On the link above, select the proper hotfix for your version of Windows Server. For SBS-users, select these:

• SBS 2008 → 2008
• SBS 2011 → 2008R2