Windows Phone 8 application terminates on back navigation

I have created WP8 application there are three pages when I navigate to the third page and then come back to Home page application just terminates with No error, The debugger stills runs in Visual Studio only Output windows shows following log: Can anyone tell me what is happening.

'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\Data\Programs\{AFD7ACFA-47D3-4AFF-A2C7-A3129A7CCF3B}\Install\Newtonsoft.Json.DLL'. Cannot find or open the PDB file.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\windows\system32\System.Threading.Tasks.ni.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\windows\system32\System.IO.ni.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\windows\system32\System.Xml.ReaderWriter.ni.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\windows\system32\System.Linq.ni.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\windows\system32\System.Collections.ni.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\Data\Programs\{AFD7ACFA-47D3-4AFF-A2C7-A3129A7CCF3B}\Install\Posh.Mako.Proxy.DLL'. Symbols loaded.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\Data\Programs\{AFD7ACFA-47D3-4AFF-A2C7-A3129A7CCF3B}\Install\System.Net.Http.DLL'. Cannot find or open the PDB file.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\Data\Programs\{AFD7ACFA-47D3-4AFF-A2C7-A3129A7CCF3B}\Install\System.Net.Http.Primitives.DLL'. Cannot find or open the PDB file.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\windows\system32\System.Threading.ni.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\Data\Programs\{AFD7ACFA-47D3-4AFF-A2C7-A3129A7CCF3B}\Install\microsoft.phone.controls.toolkit.DLL'. Cannot find or open the PDB file.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\windows\system32\System.Runtime.Extensions.ni.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'TaskHost.exe' (CLR C:\windows\system32\coreclr.dll: Silverlight AppDomain): Loaded 'C:\windows\system32\System.Globalization.ni.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
The program '[2444] TaskHost.exe' has exited with code -2147220978 (0x8004020e).