64 BIT VS 32 BIT

We created API application in 2007 and it run in 32 bit SolidWork2007/2011 in windowsXP. but now, we have a 64 bit new computer with windows 7.so we installed 64 bit Solidwork2001 in this machine.Unfortunately, my App application does not work.what  is wrong?

thanks

SolidworksApi macros