Linking problem with Three20

I'm using Three20 in my project. I added Three20 to my project using the python script supplied. Everything works fine when I compile and deploy my project onto the iphone 4 in debug mode, but when I try to build for distribution (Build and Archive) the compile fails with 2 linking errors. Does any one know what this problem might be, and why I have no problem running the project on my iphone in debug mode?

The linking error (that appears开发者_StackOverflow中文版 twice) is:

ld: file not found: ../Three20/facebook-three20-309d34e/Build/Products/Distribution-iphoneos/libThree20UICommon.a collect2: ld returned 1 exit status Command /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/g++-4.2 failed with exit code 1

Ld build/BDV.build/Distribution-iphoneos/BDV.build/Objects-normal/armv7/BDV normal armv7
cd /Users/fh/projects/iphone/BDV
setenv IPHONEOS_DEPLOYMENT_TARGET 4.2