Problem with ssh agent
Double check your permissions in those files, if they are not like this, it won’t work:

-rw-------  1 martin  staff   1675 Jul 27  2009 id_rsa
-rw-r--r--  1 martin  staff    403 Jul 27  2009 id_rsa.pub


UPDATE:
If you see that the files have an @, that means they have “extended attributes”. 

You can see what they are by issuing:

xattr -l &lt;filename&gt;