Command /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 failed with exit code 1

While running the code i am getting following errors can anyone help me with this

ld: duplicate symbol _OBJC_METACLASS_$_FBSession in /Users/Rachit/mobileapps/iphone/XYZ copy/build/ApostekApp.build/Distribution adhoc-iphoneos/APPNAME.build/Objects-normal/armv6/FBSession-B9CA0037BD5C5F44.o and /Us开发者_开发知识库ers/Rachit/mobileapps/iphone/XYZ copy/build/ApostekApp.build/Distribution adhoc-iphoneos/APPNAME.build/Objects-normal/armv6/FBSession-B9CA0037BD5C5F44.o

Command /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 failed with exit code 1

I've bumped in to this before. I am not 100% sure, but this is my theory:

This may occur when a variable is declared outside the interface in a header file. As the header file is included by several other classes, you get a conflict. If you have such a variable, try putting it inside the @implementation.

Probably not your exact problem, but may help others finding this Q.

Among other things, 'failed with exit code 1' linker errors can be caused if one of the files (.h, .m) in your project is missing.