xcode - Linker command failed with exit code 1 (use -v to see invocation) only in ipad simulator -

when build project on iphone simulator or iphone device project build. when try build on ipad simulator xcode give me errors!

duplicate symbol _immagine in:     /users/mac/library/developer/xcode/deriveddata/space_boar-avxlatycdugvvfdgfygfiidwiall/build/intermediates/space boar.build/debug-iphonesimulator/space boar.build/objects-normal/i386/introlayer.o    /users/mac/library/developer/xcode/deriveddata/space_boar-avxlatycdugvvfdgfygfiidwiall/build/intermediates/space boar.build/debug-iphonesimulator/space boar.build/objects-normal/i386/bossship.o  ld: 9 duplicate symbols architecture i386 clang: error: linker command failed exit code 1 (use -v see invocation) 

don't know why, it's strange iphone device , simulator build , ipad sim not!

this code intro image in actionlayer:

  if(ui_user_interface_idiom() == uiuserinterfaceidiompad)     {      cclabelbmfont *playlabel = [cclabelbmfont labelwithstring:@"play" fntfile:fontname];     _playitem = [ccmenuitemimage itemfromnormalimage:@"intro000ipad.png"  selectedimage:@"intro000ipad.png" target:self selector:@selector(playtapped:)];      _playitem.position = ccp(winsize.width/2, winsize.height/2);      ccmenu *menu = [ccmenu menuwithitems:_playitem, nil];     menu.position = cgpointzero;     [self addchild:menu];     /* [_playitem runaction:      [ccsequence actions:       [ccdelaytime actionwithduration:2.0],       [cceaseout actionwithaction:        [ccscaleto actionwithduration:0.5 ] rate:4.0],       nil]];*/     }     else     {           cclabelbmfont *playlabel = [cclabelbmfont labelwithstring:@"play" fntfile:fontname];         _playitem = [ccmenuitemimage itemfromnormalimage:@"intro000.png"  selectedimage:@"intro001.png" target:self selector:@selector(playtapped:)];          _playitem.position = ccp(winsize.width/2, winsize.height/2);          ccmenu *menu = [ccmenu menuwithitems:_playitem, nil];         menu.position = cgpointzero;         [self addchild:menu];           }  }