I am getting an error like this:
[WARN]Warning: Multiple build commands for output file /Developer/B/Be/build/Release-iphonesimulator/BB.app/no.png <
[WARN]Warning: Multiple build commands for output file /Developer/B/Be/build/Release-iphonesimulator/BB.app/no.png
For me the Target > Build Settings > Packaging > Product Name was set to the same thing as another value referenced in a .plist file which was custom to my app. Eventually due to our build process this creates duplicate files.