Spaces in tile categories lead to problems when used in a solidity definition.
Some generated code:
private static Solidity m_SolidNormal = new Solidity(new SolidityMapping[] {
new SolidityMapping(TileCategoryName.Solid, SolidTileShape.Value),
new SolidityMapping(TileCategoryName.Uphill, UphillTileShape.Value),
new SolidityMapping(TileCategoryName.Downhill, DownhillTileShape.Value),
new SolidityMapping(TileCategoryName.Uphill Ceiling, UpCeilingTileShape.Value),
new SolidityMapping(TileCategoryName.Downhill Ceiling, DownCeilingTileShape.Value)});