I noticed the file TSSuppRef.chm file is missing from NI TestStand 2013. However, the file exists in NI TestStand 2012. The default location is
C:\Program Files\National Instruments\TestStand 2013\Doc\Help\TSSuppRef.chm (32 Bit Windows 7).
To make a temporay fix I just copied the TSSuppRef.chm file from from TestStand 2012 to from TestStand 2013.