Android :: Phone State Listener Events Stop Receiving Sometime

My application process incoming/outgoing calls and shows some UI. So I use PhoneState Listener to listen changes such as CALL_STATE_IDLE , CALL_STATE_RINGING ,CALL_ STATE_ OFFHOOK. on receiving call to my BroacastReceiver for incoming/outgoing call. Most of the time things work properly. But sometimes my application does not receive events of Phone State Listener and hence it is not able to change/clear UI.From user feedback this typically occurs on HTC Hero. But I have came across this issue sometime on other devices also.My first guess is that android is killing my application in midway during call due to memory requirement. If so, is there any way to ensure that android does not my kill application under such situation .