The window title method is quite crap and loaded with problems.
This code works fine for me. It is basically the same as taken from ipc_pe.h. DrO comments that he couldnt get it working, though I suspect he was looking for the IPC_PE_GETINDEXINFORESULT window message instead of WM_COPYDATA.
HWND wawnd = FindWindow("Winamp v1.x", NULL);
HWND pewnd = (HWND)SendMessage(wawnd, WM_USER, 1, 260);
cbi.callback = hWnd;
cbi.index = index;
cds.dwData = IPC_PE_GETINDEXINFO;
cds.lpData = (void *)&cbi;
cds.cbData = sizeof(callbackinfo);
if (cds->dwData == IPC_PE_GETINDEXINFORESULT)
filename = cds->lpData.
As for coding it in shitty VB, I'll leave that as an exercise for the reader.
//edit: oops, the above is pseudocode, forgot the rules that you have to label it as such