我是 iPhone 开发的新手，我正在实施一个新的 facebook 分享。添加sharekit文件夹后，运行时出现以下错误：
ld: duplicate symbol _OBJC_CLASS_$_SBJSON in /Users/anil/Desktop/untitled folder 2/SMSCollection_15-10-mng/DerivedData/elsner_frmwrk/Build/Intermediates/elsner_frmwrk.build/Debug-iphonesimulator/elsner_frmwrk.build/Objects-normal/i386/SBJSON-48FA8505A9CE4B54.o and /Users/anil/Desktop/untitled folder 2/SMSCollection_15-10-mng/DerivedData/elsner_frmwrk/Build/Intermediates/elsner_frmwrk.build/Debug-iphonesimulator/elsner_frmwrk.build/Objects-normal/i386/SBJSON-D2068CA62086265C.o for architecture i386
我究竟做错了什么？