AutoStart Application not working properly

I am having a Simple AutoStart Application with TimerTask implementation, that works fine in almost many devices. The problem is that it is not working in Samsung Galaxy Y(2.3.6) and DELL XCD35(2.2) . When the device boots TimerTask works for some seconds and then shuts down. I check in the Application->Manage Application , I saw that the Applcation was already in Force Stop State. That means some how my Application gets stopped after some seconds. So, what is the reason for this weird behaviour in these two devices, if anyone has the solution do share it.

My Program stops after 2nd intent in android

My android application stops after startActivity () call of my 2nd intent. It works perfectly for the first time with intents. But on the 2nd time its control doesn't pass to 3rd activity. I haven't displayed anything on 2nd activity. Is it the problem? Or is something with my AndroidManifest.xml file? Can some one help me? I have added the intent filter of three activities as shown below.Is it the problem? I am new to android so please help me!

Difference Between Network State and WIFI State

In Permissions tab of Android Manifest, in the drop down there are options called "android.permission.ACCESS_NETWORK_STATE" and "android.permission.ACCESS_WIFI_STATE". What is the difference between them? Is ACCESS_NETWORK_STATE more generalized than ACCESS_WIFI_STATE?