Rake doc:rails aborts due to denied permission

I issue the following commands:

rails new dummy_app
cd dummy_app
rake doc:rails

When issuing the last command I notice that rake aborts due to denied
permissions. See below.

rm -r doc/api
Parsing sources
100% [485/485]

Generating Darkfish format into
rake aborted!
error generating
Permission denied

Tasks: TOP => doc:rails => doc/api/index.html
(See full trace by running task withtrace)

Performing ls -la

-rw-r–r-- 1 root admin 92997 27 Nov 23:17

Is this normal behavior? Ive googled and searched forums but to no

Im a noob to all this and am willing to do what is needed to grok this.
Can someone point me in the right direction.

(on Mac OS X 10.6)