file was built for archive which is not the architecture being linked (i386)

I’m using an addon (ofxFenster) that has static libraries for Mac, Windows and Linux, I have to drag the Mac OS only libs to my project but for some reason XCode 4 always try to use the linux version any ideas how to change that?

More info can be found in this post http://forum.openframeworks.cc/t/help-setting-a-project-from-scratch-using-ofxfenster-in-xcode-4/10290/0

Any help will be much appreciated