This is another migration issue from iOS 3.x to iOS 4.x projects.
The application does not launch in XCode when running Simulator – Debug. Instead it dies (SIGABRT) before entering main().
#0 0x91a02ef6 in __kill #1 0x91a02ee8 in kill$UNIX2003 #2 0x91a9562d in raise #3 0x91aab6e4 in abort #4 0x0245e8c9 in __springboard_unimplemented #5 0x0246d6b2 in mcount #6 0x00002298 in main at main.m:11
The answer lies here. mcount() function is profiling function. Profiling is available only on iPhone device build. The setting “Generate Profile Code” somehow gets into foobar state when you migrate the project from older XCode. Note the setting is present under both Project and Target settings so you might need to fix it under the both sections.