[Vpmedia]

[FIELDS]
...
Water0 = water/water.tga
Water1 = water/water.tga
Water2 = land/summer/fields_rock0.tga,2
Water3 = water/Beach.tga


I think that water2 or water3 (depends on the map) is missing in your ini file. Water 2 is usually for the rivers and water 3 for the sea.