Bugfix: Handle errors which happen during "async" query execution.

source/mysqlquerythread.pas

@@ -231,6 +231,7 @@ begin
         end;
       end;
     end else begin
+      try
         if ExpectResultSet(FSql) then begin
           r := RunDataQuery (FSql,TDataSet(q),ex,FCallback);
           if r then begin
@@ -243,6 +244,11 @@ begin
 
         if r then SetState (MQR_SUCCESS,'SUCCESS')
         else SetState (MQR_QUERY_FAIL,ex.Msg);
+      except
+        on E: Exception do begin
+          SetState (MQR_QUERY_FAIL,Format('%s', [E.Message]));
+        end;
+      end;
     end;
   end;