Apparently Microsoft made a change to how the networking stack in Silverlight works by moving it to a different thread. This was causing an exception when files were being uploaded to the server. After some investigation I was able to find a fix (thank you Google).

Feature List:

• Added several system prompts
  

Fix List:

• Uploading of custom prompts was fixed
• Import data upload was fixed
  
• Various popup dialog's edit and delete commands were not functioning
• Fixed playback of system and custom prompts