So after much looking around and asking questions I've come full circle. I looked deeply into LibVLC.Net and found how they were importing the DLL functions and adapted what they did to my own wrapper and it worked.
To summarize:
There are some Win32 API functions declared in the code at the start:
[DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool SetDllDirectory(string lpPathName);
[DllImport("kernel32", SetLastError = true)]
private static extern IntPtr LoadLibrary(string lpFileName);
[DllImport("kernel32", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
private static extern IntPtr GetProcAddress(IntPtr hModule, string procName);
[DllImport("kernel32.dll", SetLastError = true)]
private static extern bool FreeLibrary(IntPtr hModule);
that handle providing a handle to a dll and setting a directory search path.
I don't know exactly what it all means but when you initialize the LibVLC.Net library (the primary object) it loads pretty much EVERY function like so:
m_libvlc_media_player_new = (libvlc_media_player_new_signature)LoadDelegate<libvlc_media_player_new_signature>("libvlc_media_player_new");
That delegate is defined here like so:
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
private delegate IntPtr libvlc_media_player_new_signature(IntPtr p_instance);
//==========================================================================
private readonly libvlc_media_player_new_signature m_libvlc_media_player_new;
//==========================================================================
public IntPtr libvlc_media_player_new(IntPtr p_instance)
{
VerifyAccess();
return m_libvlc_media_player_new(p_instance);
}
And it has a public function that calls the delegate once defined.
I simply stripped down the function that defines the library instance and imported only the functionality I needed.
Thanks very much to everyone who was so patient in helping me along. I likely wouldn't have been able to come to a solution without your help.
EDIT: Okay so it wasn't that. It was the location of the LibVLC Plugin Directory. So it was something stupid -.-;