Steps to reproduce:

1. Select a Test List result from "Results" tab

2. Press on E-mail dropdown and choose "VS Results File"

The exception body:

[02/21 09:37:01,Telerik.TestStudio.Desktop.exe(440:1),Error] App.LogUnhandledException() : EXCEPTION! (see below)
     Situation: Unhandled exception!
     Outer Exception Type: System.ArgumentException
     Message: The parameter 'fileName' cannot be an empty string.
          Parameter name: fileName
     HRESULT: 0x80070057 (Official ID (if app.) = E_INVALIDARG, Error Bit = FAILED, Facility = FACILITY_WIN32, Code = ERROR_INVALID_PARAMETER)
     Call Stack:
          at System.Net.Mail.AttachmentBase.SetContentFromFile(String fileName, String mediaType)
          at System.Net.Mail.AttachmentBase..ctor(String fileName)
          at System.Net.Mail.Attachment..ctor(String fileName)
          at ArtOfTest.WebAii.Design.UI.MailUtility.OpenEmailWithAttachment(String subject, String bodyText, String attachmentFilePath)
          at ArtOfTest.WebAii.Design.UI.ResultsViewerControl.<EmailSelectedResults>d__59.MoveNext()
          --- End of stack trace from previous location where exception was thrown ---
          at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<>c.<ThrowAsync>b__6_0(Object state)
          at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
          at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)