Error: Folder name is invalid

When you open a the practical reinforcement module, you get following error message

[EN] The folder name is invalid at Borland.Delphi.TObjectHelper.Dispatch (Object Self, Object & Message) …
[NL] De map naam is ongeldig bij Borland.Delphi.TObjectHelper.Dispatch (Object Self, Object & Message) …
[FR] Le nom du dossier n’est pas valide à Borland.Delphi.TObjectHelper.Dispatch (Object Self, Object & Message) …

Solution

1. Close error message
2. Save Diamonds file
3. Close Diamonds
4. Open Diamonds + file again
5. Open Practical Reinforement Design – should now work without errors