Hi Again you need to use unwrap UVW on the model first.
Add Unwrap UVW to the modifier list
click the '+' sign next to 'Unwrap UVW in the modifier stack and choose 'Selcet Face'
select all the 5 inner faces of the box and the top face
make sure you use the correct axis in the Sub Object Params roll out (probably Z in this case) Using averaged normals wont be very good in this situation. You will see the yellow plane move about whilst selecting the faces
click on 'Planar Map', this takes a snapshot of the faces whilst looking from above.
This is where it can become a bi tricky, click 'Edit'
A new window opens (the Edit UVWs window), the faces you selected are shown here as red lines (im presuming you can see a red square within a red square, these represent the edges of the faces you have selected. (ignore the green lines for now)
make sure 'select element' at the bottom of the Edit window is checked (if you maximise this window these tools at the bottom are lost until you restore the window again so try to work with it in restored mode)
with 'select element' checked and using the move tool at the top of the Edit window (not the usual move tool on the main toolbar) hover over one of the vertices on one of the red lines and drag the square completely out of the way.
uncheck 'select element' now and click in an empty area to clear the selection.
try dragging one of the vertices on the inner square now and you will notice that it appears to be cloning itself, but in reality there are two vertices on top of each other (these relate to the upright faces selected earlier). Move all four vertices on the inner square in or out so you hopefully end up with three square within one another. try to keep the faces in proportion with themselves so as to reduce the risk of distortion/stretching when a texture is applied.
once done, close the edit window, there is no need to save this as it is automatically saved with the file.
next select the bottom face (underneath) and the 4 outside faces
make sure the z axis is still selected in the Sub Object Params roll out, then click Planr map.
Click on Edit again and you will see that the other set of line are now red.
use the same method as before to drag out the vertices into a well proportioned shape the same relative size to the previous one.
check select element at the bottom and drag the two squares next to eachother then scale them (using the scale button within the edit window) so that they fit inside the thick blue square that they were originally based. you must not go outside of this square or you will end up losing some of the texture.
you should now have two squares side by side within the thick blue square border. if so close the edit window
you can either collapse the stack to preserve the mapping or leave iot as it is, it doesnt really matter.
Go to utilities and choose texporter then click on pick object and select the box you have modelled. this will automatically render the unwrapped faces. then you can save them to whatever format you like and open it in photoshop or whatever, paint over the top and use it as a diffuse map.
Hope this helps once again
any problems let me know
Im exhausted after that!