[Radiant] Can't add page part with Shards installed?

[Marcelo Alvim]

Hi, guys.

I am currently trying out Radiant, and I have the intention of writing
an admin extension to it. It seems to me that this is easier/better
using the Shards extension, so I used Piston to import shards (from
the trunk, revision 571, which seems to be the latest) to
vendor/extensions/shards.

I also have Radiant imported from the trunk (revision 575), using
Piston, to vendor/radiant.

I am not using any other extensions, and even so I made sure, on
environment.rb, that shards was loaded before anything else.

Now, when I try to add a page part to a page, what happens is the following:
1) I click on the green plus sign on the far right
2) The little window pops up, and I write the name of my page part
3) FireBug reports an error (the console output is here:
http://pastie.caboo.se/114928)
4) Radiant goes to /admin/ui/pages/part/add, where it renders
"admin/page/_part", with no layout. The log can be seen here:
http://pastie.caboo.se/114925
5) Upon going back to the admin interface, no page parts were added.

Does anyone have a clue on why this is happening?

Thanks,
Marcelo Alvim.