There is an error in ShipclassDefS.xml for the Krynn prototype destroyer
<ShipClass>
<InternalName>ProtoTypeKrynnDestroyer</InternalName>
<DisplayName>ProtoTypeKrynnDestroyer_Class_Name</DisplayName>
<Description>ProtoTypeKrynnDestroyer_Dec</Description>
<ThumbnailOverride>Krynn_Destroyer_01T.PNG</ThumbnailOverride>
<ShipHullType>Large</ShipHullType>
<ShipRule>FavorMissile</ShipRule>
<ShipDesign>Krynn_Destroyer_01T</ShipDesign>
<AIShipClass>Assault</AIShipClass>
<StrategicIcon>Destroyer</StrategicIcon>
<BlueprintDef>DestroyerBlueprint</BlueprintDef> **** SHOULD be ProtoTypeDestroyerBlueprint
</ShipClass>
chears