Fix homework export

EduNetworkBuilder/PersonProfileForm.cs

@@ -859,7 +859,7 @@ namespace EduNetworkBuilder
             mydialog.Filter = filter;
             mydialog.Multiselect = false;
             mydialog.ShowHelp = true;
-            mydialog.CheckFileExists = true;
+            mydialog.CheckFileExists = false;
             mydialog.CheckPathExists = true;
             mydialog.AddExtension = true;
             DialogResult result = mydialog.ShowDialog();