According that, the error is typically triggered by incomplete or otherwise badly-formed kuid numbers in the texture-kuid tag. For example, very old Trainz asset configs often abbreviated Auran kuids such as <kuid:-1:12345> to just 12345, which is no longer acceptable. But check for any other syntax errors in the kuid number too. Also, the tag itself is texture-kuid, not texture.kuid as quoted in your opening post.
