Accessing DLL help - Wintel platform

I’m having trouble calling an external method from a particular DLL:

c:/Documents and Settings/brian/My Documents/galileo/PINUpdate/ol2.rb:29:in
`[]’: Unknown symbol “eximSignoffA”. (RuntimeError)

Other standard Windows DLL’s (kernel32, etc…) work fine. Does anyone know
what’s required to get a Windows DLL to talk with Ruby? I’ve tried
accessing the DLL from the Win32API module in 1.6, and I’ve tried it using
DLLoad in 1.8 - both with the same result. The DLL is a 3rd party app, so
if there are requirements for Ruby to interoperate I’ll need to articulate
that to them.

Any help is greatly appreciated!!

Brian LeRoy