I don't know if this will answer your question or not. But I way you might be able to fix it is change your mesh's material to Diffuse BSDF. Go into the Node editor and add an Image Texture Add > Texture > Image Texture. Open the image you want to use and connect the color to the color on the diffuse node. Then unwrap your mesh. Here is a screenshot. ![Screenshot ]1 Sorry if this doesn't help.
I don't know if this will help,but when i was trying to place any texture or even the uv test map(the chequer board) onto the standard cube ,only a few sides of the cube would show the texture,and the other sides of the cube would be black.
Turns out the problem was caused by the lamp(the light source).Which was lighting only the sides of the cube that it was pointing at(just like a real lamp/light would do)
So all i did was press the tab key,to change into object mode,then select the lamp and press the x key and delete the lamp.
This had me stumped for two days.
(i should also point out that this only worked for me when i use blender render.If i switch to cycles render,then the cube won't show the texture,just a solid grey coating)