Xcode Static librari error ignoring file , file was built for archive which is not the architecture being linked (armv6)

i get this error when i am trying to use my compiled static library in my iphone aplication. I have no frig开发者_StackOverflowging idea what's wrong.

ld: warning: ignoring file /Users/rw/Library/Developer/Xcode/DerivedData/MSTicketingSaaS-gkznscznevvifjesoapzgwycbces/Build/Products/Debug-iphoneos/libMylib.a, file was built for archive which is not the architecture being linked (armv6)
Undefined symbols for architecture armv6:
  "_OBJC_CLASS_$_AppData", referenced from:

It worked before upgrading to Xcode 4.0.2

I added the i386 architecture and now it compiles for the simulator but NOT for the device.

Check with lipo which is the architecture your lib has been built for:

lipo -info <path_to_lib>

If it does not contain "arm6" then you should go back to the library project and build it for the proper architecture. If this does not help, please, give more detail about the structure of your project(s).