C# – Registering 32-bit DLL on 64 bit system

I am working with some test code to create Visio documents. I am using Visual Studio 2010 on Window 7 64 bit. When I run my program and attempt to create the new Visio application object in the program I get thie following exception:

Retrieving the COM class factory for component with CLSID {00021A20-0000-0000-C000-000000000046} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)).

Here's the code that causes the exception:

Visio.Application va = new Microsoft.Office.Interop.Visio.Application();

I verified the project settings are to build a 32-bit application. I have tracked it back to 64-bit Windows can't load the 32-bit .COM Visio dll. I tried registering the dll using regsvr32 but get an error message that the entry-point DLLregisterserver was not found. MDSN says this means the file is not a valid .dll. Nowever I am trying to register the Microsoft.Office.Interop.Visio.dll from the Visual Studio libraries. Is there a fix for this? Is there a 64-bit version of the .COM libraries?