### Please describe the problem.

I'm downloading a video with 'git annex addurl' from youtube. The webapp shows the transfer, but when I click the 'web' link it takes me to a page that says "internal server error" and "Prelude.undefined"

### What steps will reproduce the problem?

1. start webapp
2. download youtube video
3. click 'web' link on transfer in git-annex

### What version of git-annex are you using? On what operating system?

* Version: 5.20140717
* OS: Debian sid

### Please provide any additional information below.

Not much in the logs, I see this:

[[!format sh """

[2014-07-25 08:40:14 BST] TransferWatcher: transfer starting: Download UUID "00000000-0000-0000-0000-000000000001" URL--quvi:https://www.youtube.com/watch,63v,61Z8_8jNLsZms Nothing
[2014-07-25 08:40:14 BST] TransferWatcher: transfer starting: Download UUID "00000000-0000-0000-0000-000000000001" Chase_Adam_at_Startup_School_NY_2014.mp4 Nothing

"""]]

> [[fixed|done]] --[[Joey]]
