HProblems making surfaces a solid object.

Hello all.  Attached is a file I have been working on.  I am trying to combine surfaces and make them a solid object.  When I go to the knit command and proceed with the operation I check the box's that say merge and make a solid.  The operation completes just fine.  But when I try and do a cross section check it still shows the body as being hollow.  Any ideas?  Thanks in advance for the help.

SolidworksParts And Features