My Apps not working for iOS 4.2.1

I have uploaded my latest iPhone Application on iTunes, Its working fine for iOS 6.0 and iOS 5 but when i have download app on iOS 4.2.1 its downloaded successfully but its not being run. Its display black screen for a moment and after crashed. Please check crash log below.

Version:         ??? (???)
Code Type:       ARM (Native)
Parent Process:  launchd [1]

Date/Time:       2012-10-25 10:20:20.830 +0100
OS Version:      iPhone OS 4.3.5 (8L1)
Report Version:  104

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x00000000
Crashed Thread:  0

    Thread 0 name:  Dispatch queue: com.apple.main-thread
    Thread 0 Crashed:
    0   MeteorElectrical                0x0002d12a 0x1000 + 180522
    1   MeteorElectrical                0x0000268e 0x1000 + 5774
    2   UIKit                           0x3503281a 0x34ffd000 + 219162
    3   UIKit                           0x3502cb5e 0x34ffd000 + 195422
    4   UIKit                           0x350017d0 0x34ffd000 + 18384
    5   UIKit                           0x3500120e 0x34ffd000 + 16910
    6   UIKit                           0x35000c4c 0x34ffd000 + 15436
    7   GraphicsServices                0x3593be70 0x35937000 + 20080
    8   CoreFoundation                  0x361eea90 0x36179000 + 481936
    9   CoreFoundation                  0x361f0838 0x36179000 + 489528
    10  CoreFoundation                  0x361f1606 0x36179000 + 493062
    11  CoreFoundation                  0x36181ebc 0x36179000 + 36540
    12  CoreFoundation                  0x36181dc4 0x36179000 + 36292
    13  UIKit                           0x3502bd42 0x34ffd000 + 191810
    14  UIKit                           0x35029800 0x34ffd000 + 182272
    15  MeteorElectrical                0x0000214e 0x1000 + 4430
    16  MeteorElectrical                0x000020e0 0x1000 + 4320

    Thread 1:
    0   libsystem_kernel.dylib          0x33ec03ec 0x33eae000 + 74732
    1   libsystem_c.dylib               0x33efa6d8 0x33ec6000 + 214744
    2   libsystem_c.dylib               0x33efabbc 0x33ec6000 + 215996

    Thread 2 name:  Dispatch queue: com.apple.libdispatch-manager
    Thread 2:
    0   libsystem_kernel.dylib          0x33ec0fbc 0x33eae000 + 77756
    1   libdispatch.dylib               0x33091032 0x3308b000 + 24626
    2   libdispatch.dylib               0x3309203a 0x3308b000 + 28730
    3   libdispatch.dylib               0x330915ea 0x3308b000 + 26090
    4   libsystem_c.dylib               0x33efa58a 0x33ec6000 + 214410
    5   libsystem_c.dylib               0x33efabbc 0x33ec6000 + 215996

    Thread 3 name:  WebThread
    Thread 3:
    0   libsystem_kernel.dylib          0x33ebdc00 0x33eae000 + 64512
    1   libsystem_kernel.dylib          0x33ebd758 0x33eae000 + 63320
    2   CoreFoundation                  0x361ef2b8 0x36179000 + 484024
    3   CoreFoundation                  0x361f1562 0x36179000 + 492898
    4   CoreFoundation                  0x36181ebc 0x36179000 + 36540
    5   CoreFoundation                  0x36181dc4 0x36179000 + 36292
    6   WebCore                         0x3594a27e 0x35944000 + 25214
    7   libsystem_c.dylib               0x33ef930a 0x33ec6000 + 209674
    8   libsystem_c.dylib               0x33efabb4 0x33ec6000 + 215988

    Thread 0 crashed with ARM Thread State:
        r0: 0x00000000    r1: 0x00066310      r2: 0x3ee32fa8      r3: 0x3e784400
        r4: 0x0019a790    r5: 0x352ee670      r6: 0x36259dd8      r7: 0x2fdfe348
        r8: 0x000665a8    r9: 0x3e796418     r10: 0x352ee690     r11: 0x352f46c0
        ip: 0x345cc72d    sp: 0x2fdfe328      lr: 0x0002d111      pc: 0x0002d12a
      cpsr: 0x20000030

Please help me if you have any idea about this.

Please check if you have added such functionality that only works in IOS 5 or later & in older Ios it gives warning. That'll possibly make your Application not work in older Ios. Hope this helps.