solve error : "Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/llvm-gcc-4.2 failed with exit code 1"

In my application I have integrate Three20 Library and Restkit framework, after this I am Build the code the error was generated the error is :

     `"Command /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/llvm-gcc-4.2 failed with exit code 1"`

and the error description is

  ld: duplicate symbol _OBJC_METACLASS_$_RKJSONParser in /Users/pratikkanada/Desktop/Zipogo/Zipongo - working     
  version/RestKit/Build/Release-iphonesimulator/libRestKitJSONParserYAJL.a(RKJSONParser+YAJL.o) and 
  /Users/pratikkanada/开发者_运维问答Desktop/Zipogo/Zipongo - working version/RestKit/Build/Release-
  iphonesimulator/libRestKitJSONParserSBJSON.a(RKJSONParser+SBJSON.o)

so, pls tell me how to solve this error

It seems that you have added that lib two times.

Please search libRestKitJSONParserSBJSON.a and (RKJSONParser+SBJSON.o) in entire code and you may found one of these added two times.

Simply solution is remove any one of two same files.