Can´t delete the lines

[gnicar]

Hi guys, im new here, i started it with wings a few days, is an amazing software! it helped me a lot with uv mapping but i have a problem right now that i don´t know how to solve.

I made a wall with a window in Sketchup and then i imported it into wings, but i cant delete all those lines on the wall, here is an image i took:

http://k33.kn3.net/4/5/1/F/2/6/CEB.png

How i can delete all those black lines to make the wall like sketchup (blue lines) only, this is frustrating because of those lines i can´t make a proper uv mapping. i make the right cuts but the uv map always appear in little pieces.

I hope you can help me guys, by the way, sorry for my English, it´s not my native language. Thanks in advanced