Cancel sometimes crashes in 0.26

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Start a save operation (e.g. saving the audio stream)
2. Cancel the activity

What is the expected output? What do you see instead?
I expect Subler to abort it's current work and return me to the main window. 
Instead, Subler crashes.

What version of the product are you using? On what operating system?
The 0.26 beta.

Please provide any additional information below.
Crash log attached.

Original issue reported on code.google.com by j...@jonsview.com on 18 Oct 2014 at 3:51

Attachments:

• [Subler crash log.rtf](https://storage.googleapis.com/google-code-attachments/subler/issue-771/comment-0/Subler crash log.rtf)