[AccessD] Access 32 vs 64-bit

Hello. I developed a 32-bit Access 2007 app with VBA code that uses DAO
exclusively for data access and has no add-ins. My client has Windows 7
64-bit PCs running Office 2010 64-bit. I delivered the app as a 2007 runtime
package and it didn't work at their place. 
The app runs fine on my WinServer2008 machine with Office 2010 32-bit, but I
haven't tested it under Office 2010 64-bit.
Since my other clients are still operating in the 32-bit world, I can't
abandon the 32-bit version.
Is there a way to satisfy both worlds with just one version?

Thanx,
DB