For textures you could be hitting the max on the card running with those high maps, you might have the prefs set too low to display the ones you have in there.

You could see what the variable thats being assigned is to see if you can fix the error (as thats what its saying)

Its looking ok, so far, if your going with old raggidy sails I would make the transprancy map first (to get some holes and that) then apply the colour map to that.

A lot of this will come form the variations in the colour maps, and it will set the scale of the project to.