Transparent cylinders?

[Fonte Boa]

I'm not sure about one thing: do you have any image/texture applied on these objects? Just open Outliner window and verify if there is some image/texture present.

Another question: in Outliner windows, do you have some material beyond Default one? Could you, please, click on the material with right button, call Edit Material... and verify if there is some texture present?

While you answer me, please verify which ones of the following commands at top menu are checked:
View / Show / Show Colors
View / Show / Show Materials
View / Show / Show Textures

EDIT:
Isnt there a complete transparent 32-bits image/texture applied to the (uv-mapped) object?