Setting up Podcast Server: error 256, message says uninitalized constant ActiveSupport::Dependencies::Mutex

Settings up podcast server for the first time, everything seems fine, but the Configure Podcast Producer helper fails on setup.

the error in the Server log, which repeats is:

Loaded Podcast Library ...

Migrating database: ... /db.sqlite3

... setup_pcastserverd_library failed: 256

also interesting is the Error log, which repeats:

rake/rdoctask is deprecated, Use rdoc/task instead (in RDoc 2.4.2+)

rake aborted!

uninitialized constant ActiveSupport::Dependencies::Mutex

(See full trace by running task with --trace)

I've tried changing the location of the Library, doing the standard as opposed to the express setup and turning off the Podcast Capture web application (which turns itself back on on save). Xgrid also works, with single signon and i'm using OD w/ Kerberos.

I host some rails apps on the same machine, so it's possible that i've updated past whatever the podcast server needs (as it seems to be written in ruby, and obviously uses rake) but It seems weird that the server wouldn't catch these dependancies.

Any help would be much appreciated, thanks.