I tried to run Xcode apps on my jailbroken iPod Touch 2G by using JailCoder (which seems to be doing its job) and AppSync on my iPod touch (running iOS v4.2.1, the highest allowed for armv6 I believe) and got this error message for every build.
I just restored my iPod touch about 3 weeks ago and promptly jailbroke it. And it worked fine since except for this. Even blank template Xcode projects, which and runs perfect on both the iPhone and iPad simulators always gets this fatal error and this one exclusively. I even make sure to set the deployment target to 4.2 and make sure armv6 and armv7 are both supported.
/bin/sh -c /Users/Zach/Library/Developer/Xcode/DerivedData/test-run-ddvzosbhsvraawfdopekdoyocney/Build/Intermediates/test-run.build/Debug-iphoneos/test-run.build/Script-50524F424C454D533F.sh
iPhone Developer: ambiguous (matches "iPhone Developer" and "iPhone Developer" in /Users/Zach/Library/Keychains/login.keychain)
Command /bin/sh failed with exit code 1