Just figured I'd help you out with further releases, I'll give you some pointers.
Firstly, you said if the file's already deleted you will get an error. Use this code for proper coding:
Also, you said you can't delete ahnrpt. That's because its default settings set it to as 'Read-Only', so use this code to change that:
If My.Computer.FileSystem.FileExists("File you want to delete") = True Then
Hope this helps.
If My.Computer.FileSystem.FileExists("Path to Ahnrpt") Then
System****.File.SetAttributes("Path to Ahnrpt"), IO.FileAttributes.Normal)
My.Computer.FileSystem.DeleteFile("Path to AhnRpt")