ZipArchive library compile error

i have included libz.1.2.3.dylib

after insert code

ZipArchive* za = [[ZipArchive alloc] init];

error when compile

 "_OBJC_CLASS_$_ZipArchive", referenced from:

UPDATE

according to http://code.google.com/p/ziparchive/wiki/PageName

i have include ZipArchive folder to project, and and framework libz.1.2.3.dylib.

then i try to unzip file on iphone but it error about framework. how to resolve it?

Ld build/ePUBreader.build/Debug-iphoneos/ePUBreader.build/Objects-normal/armv7/ePUBreader normal armv7
cd /Users/ragopor/Desktop/ePUBreader
setenv IPHONEOS_DEPLOYMENT_TARGET 4.0
setenv PATH "/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc-4.2 -arch armv7 -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.1.sdk -L/Users/ragopor/Desktop/ePUBreader/build/Debug-iphoneos -F/Users/ragopor/Desktop/ePUBreader/build/Debug-iphoneos -filelist /Users/ragopor/Desktop/ePUBreader/build/ePUBreader.build/Debug-iphoneos/ePUBreader.build/Objects-normal/armv7/ePUBreader.LinkFileList -dead_strip -miphoneos-version-min=4.0 -framework Foundation -framework UIKit -framework CoreGraphics -framework StoreKit -lz.1.2.3 -o /Users/ragopor/Desktop/ePUBreader/build/ePUBreader.build/Debug-iphoneos/ePUBreader.build/Objects-normal/armv7/ePUBreader

Undefined symbols:
  "_OBJC_CLASS_$_ZipArchive", referenced from:
      objc-class-ref-to-ZipArchive in ePUBreaderAppDelegate.o
ld: symbol(s) not found
collect2: ld returned 1 exit status