When you are going to install LSP on windows 7 64 bit, it is vital to understand that you have two separate running applications – 32-bit and 64-bit.  These both load the compatible DLL.  Therefore, the 32-bit application loads a 32-bit LSP and the same is true with the 64-bit.  This installed layered service provider is specific.  The windows 7 OS maintains both kinds of catalogs and if you want to support the 64-bit platform you must install both (32 and 64-bit) versions of your LSP (using a specific installer for each).

Chris