(Diffuse only PNG) making object transparent?

A DTS object is coming up being darkly transparent in the game. Where characters and the environment can be seen though it. With no shadow. A basic .PNG image with "NO alpha transparency" is only attached to the diffuse. No opacity is used or checked marked. This problem is the same when using a PNG WITH a transparent alpha exported as a DTS in the Diffuse only. If both diffuse and opacity is used, the transparency alpha is seen, with the same darkly transparent error.

It does work fine in game with shadows when...
A basic Material shader is applied.
A JPG image is applied, instead of using both Alpha or Non-alpha PNG.