Hello Audrey,
Be careful with the examples. For several of them, there is always water during the computation. Thus the domain is wet without dry nodes. This enables to use an optimised option to skip tests if a special treatment is to be done for dry nodes (TIDAL FLATS = NO). It only works when every node is always wet during the computation otherwise the computation crashes as yours.
My recommendation is to use TIDAL FLATS = YES as it is the default choice and especially when you do not know what will be the behaviour of the computation. The use of choice NO is to be done only if you are fully sure there is no dry areas.
I would recommend you to read the user manuals and think why you change the default options if changed.
Hope this helps,
Chi-Tuan