error window on crop shot

What steps will reproduce the problem?
1. initiate crop shot
2. take the shot
3. error window appears

What is the expected output? What do you see instead?

expected output is the screenshot in the defined output folder location. i do 
not see the cropped image in the output folder

What version of the product are you using? On what operating system?
version 4.9.0 Rev 3033 on Windows 7 32-bit enterprise edition

Copy text from Debug tab
System.NullReferenceException: Object reference not set to an instance of an 
object.
   at ZScreenLib.FileSystem.GetUniqueFileName(Workflow workflow, String fileName) in D:\Users\Mike\Documents\Visual Studio 2010\Projects\ZApps\trunk\ZScreenLib\Global\FileSystem.cs:line 275
   at ZScreenLib.FileSystem.GetUniqueFilePath(Workflow workflow, String dir, String fileName) in D:\Users\Mike\Documents\Visual Studio 2010\Projects\ZApps\trunk\ZScreenLib\Global\FileSystem.cs:line 311
   at ZScreenLib.FileSystem.WriteImage(String fp, Stream stream) in D:\Users\Mike\Documents\Visual Studio 2010\Projects\ZApps\trunk\ZScreenLib\Global\FileSystem.cs:line 89
   at ZScreenLib.WorkerTask.WriteImage(Image img) in D:\Users\Mike\Documents\Visual Studio 2010\Projects\ZApps\trunk\ZScreenLib\Helpers\WorkerTask.cs:line 2135
   at ZScreenLib.WorkerTask.PublishData() in D:\Users\Mike\Documents\Visual Studio 2010\Projects\ZApps\trunk\ZScreenLib\Helpers\WorkerTask.cs:line 1483
   at ZScreenGUI.ZScreen.BwApp_DoWork(Object sender, DoWorkEventArgs e) in D:\Users\Mike\Documents\Visual Studio 2010\Projects\ZApps\trunk\ZScreen\Forms\ZScreenWorker.cs:line 74
   at System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e)
   at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)

Please provide any additional information below.

Original issue reported on code.google.com by Rej...@gmail.com on 9 Aug 2012 at 10:58

Attachments:

[error window.png](https://storage.googleapis.com/google-code-attachments/zscreen/issue-835/comment-0/error window.png)

tinman83 / zscreen

error window on crop shot #835