ERROR_INVALID_HANDLE

Question

I am trying to use the following functions defined in mpusbapi.h

HANDLE(*MPUSBOpen)(DWORD instance,     //Input
                   PCHAR pVID_PID,     //Input identifier
                   PCHAR pEP,          //Input pipe
                   DWORD dwDir,        //Input
                   DWORD dwReserved);  //Input <Future Use>

DWORD(*MPUSBWrite)(HANDLE handle,          //Input
                   PVOID pData,            //Input
                   DWORD dwLen,            //Input
                   PDWORD pLength,         //Output
                   DWORD dwMilliseconds);  //Input

When I use these in my test.cpp, it looks like;

HANDLE LACOutpipe;
pipeName="\\MCHP_EP";
PCHAR VidPid="vid_04d8&pid_fc5f";
BYTE bufData[3];
DWORD buflen=sizeof(bufData);
DWORD bufProcessed;

LACOutpipe=MPUSBOpen(0,        //only one device connected, dont need to check for multiple
                     VidPid,   //this is the device driver vid and pid
                     pipeName, //the pipe to write to?
                     MP_WRITE, //MP_WRITE is just 1
                     0);       //not supported yet?
cout<<LACOutpipe<<endl;

//now use LACOutpipe handle to write

cout<<MPUSBWRITE(LACOutpipe,   //the handle to write to
               bufData,        //BYTE array with data to be sent
               bufLen,         //length of bufData
               &bufProcessed,  //bytes processed
               10000)          //10 second timeout
               <<endl;

cout<<GetLastError()<<endl;

The console output is:

FFFFFFFF
0
6
Press any key to continue...

MPUSBWrite returning 0 means that the write function failed. Error code 6 corresponds to ERROR_INVALID_HANDLE: The handle is invalid.

Anyone know why? I have a hunch it is the pipeName but not sure how to check/fix this.