There's a program I help support that's written in VB, and it's been having a problem printing (labels, in this particular application) on one guy's PC, but no where else.  It dies when it goes into a call to SendMessage and doesn't return; I'll elaborate:

l = SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0, "windows")


where   Public Const HWND_BROADCAST = &HFFFF
            Public Const WM_WININICHANGE = &H1A

and

Declare Function SendMessage Lib "user32" _
         Alias "SendMessageA" _
         (ByVal hwnd As Long, _
         ByVal wMsg As Long, _
         ByVal wParam As Long, _
         lParam As String) As Long


What could there be wrong that might cause problems on one PC, but is OK everywhere else?  Thanks for any input.