As of 2012-05-28, there’s very little support for running Darts editor on 64-bit Linux (and in general on non-ubuntu linux).
In order to run the modified version of chromium shipped with the editor, I had to do a little hack.
Luckily, I already have a 32-bit squeeze chroot on my system (using schroot), but nevertheless I wasn’t able to run the whole IDE in the chroot; instead I had to substitute the actual chrome executable with a wrapper script that runs it through the chroot.
First of all, download the DartEditor from http://www.dartlang.org/downloads.html.
Then, unzip the package and go in the dart-sdk/chromium directory.
Rename chrome to the-actual-chrome, then create a script named chrome with the following content:
#!/bin/bash
schroot -c squeeze32 -- env DISPLAY=:0 $( dirname "$0" )/the-actual-chrome "$@"
Warning
For this to work, you’ll need a working Debian 32bit chroot, named squeeze32.