Work-arounds for Windows Vista:

Do not specify an init function, apparently not supported by Vista -
RegisterModule() fails with AX=1 when an InitFunc is specified.
Use AX to get the VDD handle (required for UART virtualization),
even though this value does not match the handle that was passed
to VDDInitialize().

src/sbbs3/sbbsexec.c

@@ -77,7 +77,6 @@ HANDLE		hungup_event=NULL;
 HANDLE		interrupt_event=NULL;
 HANDLE		rdslot=INVALID_HANDLE_VALUE;
 HANDLE		wrslot=INVALID_HANDLE_VALUE;
-HANDLE		vdd_handle;
 RingBuf		rdbuf;
 str_list_t	ini;
 char		ini_fname[MAX_PATH+1];
@@ -461,13 +460,15 @@ __declspec(dllexport) void __cdecl VDDDispatch(void)
 	retval=0;
 	node_num=getBH();
 
-	lprintf(LOG_DEBUG,"VDD_OP: %d (arg=%X)", getBL(),getCX());
+	lprintf(LOG_DEBUG,"VDD_OP: (handle=%d) %d (arg=%X)", getAX(),getBL(),getCX());
 	vdd_calls++;
 
 	switch(getBL()) {
 
 		case VDD_OPEN:
 
+			sscanf("$Revision$", "%*s %s", revision);
+
 			lprintf(LOG_INFO,"Synchronet Virtual Device Driver, rev %s %s %s"
 				,revision, __DATE__, __TIME__);
 #if 0
@@ -545,7 +546,7 @@ __declspec(dllexport) void __cdecl VDDDispatch(void)
 				PortRange.First=uart_io_base;
 				PortRange.Last=uart_io_base + UART_IO_RANGE;
 
-				VDDInstallIOHook(vdd_handle, 1, &PortRange, &IOHandlers);
+				VDDInstallIOHook((HANDLE)getAX(), 1, &PortRange, &IOHandlers);
 
 				interrupt_event=CreateEvent(NULL,FALSE,FALSE,NULL);
 				InitializeCriticalSection(&interrupt_mutex);
@@ -570,7 +571,7 @@ __declspec(dllexport) void __cdecl VDDDispatch(void)
 
 			if(virtualize_uart) {
 				lprintf(LOG_INFO,"Uninstalling Virtualizaed UART IO Hook");
-				VDDDeInstallIOHook(vdd_handle, 1, &PortRange);
+				VDDDeInstallIOHook((HANDLE)getAX(), 1, &PortRange);
 			}
 
 			CloseHandle(rdslot);
@@ -779,13 +780,3 @@ __declspec(dllexport) void __cdecl VDDDispatch(void)
 	}
 	setAX((WORD)retval);
 }
-
-__declspec(dllexport) BOOL __cdecl VDDInitialize(IN PVOID hVDD, IN ULONG Reason, 
-IN PCONTEXT Context OPTIONAL)
-{
-	sscanf("$Revision$", "%*s %s", revision);
-
-	vdd_handle=hVDD;
-
-    return TRUE;
-}