Xcode - "no such file or directory" for headers

I'm hoping that somebody with some experience of iOS development can help with this issue.

I'm working with PhoneGap and ZXing. I've follow开发者_如何学运维ed the enclosed readme, as well as these instructions: http://yannickloriot.com/2011/04/how-to-install-zxing-in-xcode-4/

PhoneGap plugin: https://github.com/phonegap/phonegap-plugins/tree/master/iPhone/BarcodeScanner

It seems many others have experienced this problem. When I compile, I get these errors:

 ZXingWidgetController.h: No such file or directory
 QRCodeReader.h: No such file or directory

In my project -> Build Settings -> Header Search Paths, I have defined:

 $(SRCROOT)/zxing/cpp/core/src/
 $(SRCROOT)/zxing/iphone/ZXingWidget/Classes (recursive)

I have checked the locations of those folders, and they match what is defined in the header search paths. In the plugins folder, the file "BarcodeScanner.h" has these lines, where the errors are being produced:

#import "ZXingWidgetController.h"
#import "QRCodeReader.h"

Any ideas? I've scoured the Internet and tried just about everything. I'm just about to go insane.

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It sounds like it's an old project.

I'd create a new project. The header search paths shouldn't be needed.

Then add all the files in the original project to the new one. (Of course, there may be a few subtleties that being familiar with iOS would make easier.)