Mouse Controlled Character and Colliders

Hi, im having some problems with my mouse controlled character, its going through buildings even when they have colliders. I've tried all the colliders and none prevent the character from going through. I was able to find a work around by adding a rigid body on the character and freezing position on X and Y, and freezing rotation on X, Y and Z. This way the character doesnt go through buildings but whenever I click on the position I want him to go he keeps sliding (because I didnt freeze position on Z). Any solution for my problem? Heres a screenshot of the problem: http://img534.imageshack.us/img534/5138/colliders.jpg Regards, ExyloN