GNU Debugger (gdb) is used to analyze the run time behavior of an iOS application. In recent iOS versions, GNU Debugger directly downloaded from the Cydia is broken and not functioning properly. Following the Pod 2g blog post also did not help me.
To get rid of this problem, add http://cydia.radare.org to cydia source and download the latest GNU Debugger (build 1708). GDB build 1708 is working for iOS 5.x.