I did what you said to the letter, and yeah, I got stuck on something to do with FIELD_OFFSET, Im not touching Ogre yet though.
..\..\ois_0-5-0-Windows\ois\src\win32\Win32JoyStick.cpp:290: error: a casts to a type other than an integral or enumeration type cannot appear in a constant-expression
Edit: Odd, that error came up when using MiniGW as the compiler, but I tried switching to VC++ 2003 Toolkit and it seemed to compile fine, OIS.lib file outputted, Ill try using it.