A dirty error was occuring while I was compiling an iPhone app to deploy in my iPhone v2.2.1. I thought I need to go back to developer mode to fix this, but luckily I found a quick solution to this which was fairly simple than anything else in Cocoa coding. I would definitely want to share this with you coz it looks quite common error to me. Likely to be an Xcode bug too:
Error description, "Command /Developer/usr/bin/ibtool failed with exit code 5"
Clue: UITextFields can’t be set to Hidden !!!
The solution is: You probably have a UITextField set to hidden in one of your Nib files… Unhiding the UITextField will solve the problem.