start index cannot be larger than length of string

merhabalr winservere 2012 için bir uygulama yazdım 

bu uygulama bir log dosyasını timer la her saniye tekrar tekrar kopyalıyarak bir txt dosyası olarak ayrı bir dizinde kaydediyor ve kaydettiği txt dosyasını başka bir timer le tekrar işleme tutuyor fakat işlemi başlattıktan sonra yani 2.ci timer ı enable yaptıktan sonra

start index cannot be larger than length of string

hatası aldığım bir pencere açılıyor hatanın detaylarında ise

aşağıdaki mesajı alıyorum 

 

See the end of this message for details on invoking 

just-in-time (JIT) debugging instead of this dialog box.

*********** Exception Text ********

System.ArgumentOutOfRangeException: startIndex cannot be larger than length of string.

Parameter name: startIndex

   at System.String.InternalSubStringWithChecks(Int32 startIndex, Int32 length, Boolean fAlwaysCopy)

   at _140202Win_anaproje.Form1.timer1_Tick(Object sender, EventArgs e)

   at System.Windows.Forms.Timer.TimerNativeWindow.WndProc(Message& m)

   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

******** Loaded Assemblies ********

mscorlib

    Assembly Version: 4.0.0.0

    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL

    CodeBase: file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/mscorlib.dll

----------------------------------------

140202Win_anaproje

    Assembly Version: 1.0.0.0

    Win32 Version: 1.0.0.0

    CodeBase: file:///C:/Users/Administrator/Desktop/140202Win_anaproje.exe

----------------------------------------

System.Windows.Forms

    Assembly Version: 4.0.0.0

    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL

    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll

----------------------------------------

System.Drawing

    Assembly Version: 4.0.0.0

    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL

    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll

----------------------------------------

System

    Assembly Version: 4.0.0.0

    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL

    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll

----------------------------------------

System.Configuration

    Assembly Version: 4.0.0.0

    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL

    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll

----------------------------------------

System.Xml

    Assembly Version: 4.0.0.0

    Win32 Version: 4.0.30319.17929 built by: FX45RTMREL

    CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll

----------------------------------------

******** JIT Debugging ***********

To enable just-in-time (JIT) debugging, the .config file for this

application or computer (machine.config) must have the

jitDebugging value set in the system.windows.forms section.

The application must also be compiled with debugging

enabled.

For example:

<configuration>

    <system.windows.forms jitDebugging="true" />

</configuration>

When JIT debugging is enabled, any unhandled exception

will be sent to the JIT debugger registered on the computer

rather than be handled by this dialog box.