Messed textures when importing models

Im sorry, if there’s already a thread about this problem, but didn’t find anything.

Well, the problem is when I import some models and the textures of model just mess up. They look like they are streched or something… I think it would be some problem with shading/lights, because when I enable ‘shadeless’-option on material-tab, the model looks like just normal. Here are some pics.

Shadeless-option enabled, and model looks like normal…

…and this is the problem, when shadeless-option is disabled…

I have spent a lot lot of time trying to solve this annoying problem, so I’ll be very thankful for your help.

can you upload the blend file? it could be the material you’re applying doesn’t have an alpha option to mask out the transparency