Index: /trunk/src/VBox/Additions/WINNT/VBoxGuest/VBoxGuest.cpp
===================================================================
--- /trunk/src/VBox/Additions/WINNT/VBoxGuest/VBoxGuest.cpp	(revision 29368)
+++ /trunk/src/VBox/Additions/WINNT/VBoxGuest/VBoxGuest.cpp	(revision 29369)
@@ -965,4 +965,5 @@
             if (!vmmdevGetRequestSize(requestHeader->requestType))
             {
+                dprintf(("VBoxGuest::VBoxGuestDeviceControl: vmmdevGetRequestSize failed!\n")); \
                 Status = STATUS_INVALID_PARAMETER;
                 break;
@@ -1008,4 +1009,5 @@
             else
             {
+                dprintf(("VBoxGuest::VBoxGuestDeviceControl: VbglGRAlloc failed!\n")); \
                 Status = STATUS_UNSUCCESSFUL;
             }