模拟器ios4.3中应用崩溃

应用在ios5.1和ios6.1中运行正常，但是放到ios4.3中就崩溃了。

出问题的代码：

[self.tabBarItem setFinishedSelectedImage:[UIImage imageNamed:@"home-active.png"] withFinishedUnselectedImage:[UIImage imageNamed:@"home-normal"]];
``

代码实现设置TabBar的图片。

log：
2013-03-08 15:16:27.688 GrandNatural[3372:12c03] -[UITabBarItem setFinishedSelectedImage:withFinishedUnselectedImage:]: unrecognized selector sent to instance 0x628c090
2013-03-08 15:16:27.690 GrandNatural[3372:12c03] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UITabBarItem setFinishedSelectedImage:withFinishedUnselectedImage:]: unrecognized selector sent to instance 0x628c090'
* Call stack at first throw:
(

0   CoreFoundation                      0x019785a9 __exceptionPreprocess + 185
1   libobjc.A.dylib                     0x016e7313 objc_exception_throw + 44
2   CoreFoundation                      0x0197a0bb -[NSObject(NSObject) doesNotRecognizeSelector:] + 187
3   CoreFoundation                      0x018e9966 ___forwarding___ + 966
4   CoreFoundation                      0x018e9522 _CF_forwarding_prep_0 + 50
5   GrandNatural                        0x0000f8fe -[HomeViewController initWithNibName:bundle:] + 535
6   GrandNatural                        0x00002985 -[GrandNaturalAppDelegate application:didFinishLaunchingWithOptions:] + 262
7   UIKit                               0x00ce5c89 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 1163
8   UIKit                               0x00ce7d88 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 439
9   UIKit                               0x00cf2617 -[UIApplication handleEvent:withNewEvent:] + 1533
10  UIKit                               0x00ceaabf -[UIApplication sendEvent:] + 71
11  UIKit                               0x00ceff2e _UIApplicationHandleEvent + 7576
12  GraphicsServices                    0x021dd992 PurpleEventCallback + 1550
13  CoreFoundation                      0x01959944 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 52
14  CoreFoundation                      0x018b9cf7 __CFRunLoopDoSource1 + 215
15  CoreFoundation                      0x018b6f83 __CFRunLoopRun + 979
16  CoreFoundation                      0x018b6840 CFRunLoopRunSpecific + 208
17  CoreFoundation                      0x018b6761 CFRunLoopRunInMode + 97
18  UIKit                               0x00ce77d2 -[UIApplication _run] + 623
19  UIKit                               0x00cf3c93 UIApplicationMain + 1160
20  GrandNatural                        0x00002856 main + 132
21  GrandNatural                        0x00002795 start + 53

)
terminate called throwing an exception(lldb)