user.exe: Don't try calling the WH_CALLWNDPROC hook if no hook was set.
diff --git a/dlls/user.exe16/hook.c b/dlls/user.exe16/hook.c
index 105254e..d140e16 100644
--- a/dlls/user.exe16/hook.c
+++ b/dlls/user.exe16/hook.c
@@ -192,7 +192,7 @@
     CWPSTRUCT16 cwp;
     struct hook16_queue_info *info = get_hook_info( FALSE );
 
-    if (!info->proc[WH_CALLWNDPROC - WH_MINHOOK]) return;
+    if (!info || !info->proc[WH_CALLWNDPROC - WH_MINHOOK]) return;
 
     cwp.hwnd    = hwnd;
     cwp.message = msg;