all the other chroots are now fucked because we did as you asked, and
for some reason it wants to bring in mlton-doc
The problem there is you're trying to install and/or upgrade the sid one, not the squeeze one.
I think we won't be doing anything like that again any time soon.
Feel free to purge whatever mlton package you have installed.
I've been fairly successful building the package from installing the .debs in my home directory.