I have problem with my application. when i run the application it gives an error "there is no source code available for the current location". Even i try to debug using f8 and msgbox in all forms, It doesn go thru it.I dont know what goes wrong with my application. All the while it goes perfectly alright.Please help me, what does this error message meant and why all the way in sudden it happens to be like this?

normally this error only pops up when you do step through debugging and trying to debug third party assemblies.
You can try to enable/disable managed code debugging.
Go to your project properties -> Debug -> Enable unmanaged code debugging

thank you so much, Its working now.