Quartz error

Could you post a link to the demo you are following. A lot has chaged in Xcode and Apple doesn't always keep all the demos up to date.

I haven't gone through the tutorial you're going through (the Apple tutorial Designing a User Interface with Interface Builder), but a Google search for the error message "ibtool failed with exit code 255" uncovered a possible solution. Someone fixed the problem by turning off auto layout, which is an Interface Builder feature that was added after the tutorial was written. To turn off auto layout, select the xib file from the project navigator on the left side of the project window. Open the file inspector by choosing View > Utilities > Show File Inspector. Deselect the Use Auto Layout checkbox in the file inspector.

If turning off auto layout doesn't fix the problem, another thing I noticed is you have a space in the path to QCDemo, Xcode File. I saw on Stack Overflow that an exit code 255 can occur if a file can't be found. Rename the folder Xcode File to something without spaces and see if the project builds. If that doesn't work, check the connections (actions, outlets, and bindings) in the xib file to make sure they match the tutorial. The problem is somewhere in the xib file.