(svn r24388) -Fix [FS#5233]: Do not consider not finding a particular base set critical; just load a different one and display an in-game error later on.

src/error.h

@@ -48,6 +48,8 @@ public:
 	void CopyOutDParams();
 };
 
+void ScheduleErrorMessage(const ErrorMessageData &data);
+
 void ShowErrorMessage(StringID summary_msg, StringID detailed_msg, WarningLevel wl, int x = 0, int y = 0, uint textref_stack_size = 0, const uint32 *textref_stack = NULL);
 void ClearErrorMessages();
 void ShowFirstError();