I upgraded to 2015 recently and none of my old equations would work. Anything I would try to type in to the Equation Manager said the Syntax was incorrect.  The problem was the swvba.tlb file.  Search your C drive for "swvba". Find the one with the "tlb" extension.  Mine was located in C/ProgramFiles/SolidWorksCorp/Solidworks. I copied that file into  C/ProgramFiles/CommonFiles/SOLIDWORKSShared , and it worked. I also renamed the original file "swvba2.tlb" just in case something went wrong. Then I could find it and just change its name back. I advise you do the same, but everything worked and I left it as "swvba2.tlb".Upon restarting the program, I noticed that swvba.tlb is back in its original location, next to my #2 file, but everything is working as it should. So the correct location for swvba.tlb appears to be the SolidworksShared Folder. Copy one there and you should be ok.

-Mike