I had some problems running IT Mill toolkit development environment, or the hosted mode actually, on 64-bit linux (Ubuntu Hardy in my case). Fortunately, there is a workaround, which is explained below.
To get the hosted mode running on 64-bit linux see comments 39 and 41 of the following GWT ticket
http://code.google.com/p/google-web-toolkit/issues/detail?id=134
The problem is actually in the Google Web Toolkit and it is explained in the aforementioned ticket: “The GWT hosted web browser ships with a 32-bit version of the SWT bindings, so the browser does not work in 64-bit Linux.”
If you have the same problem the ending of the error message looks something like this “…/itmill-toolkit-linux-5.2.8/gwt/libswt-pi-gtk-3235.so: wrong ELF class: ELFCLASS32 (Possible cause: architecture word width mismatch)”
Hopefully this helps someone other as well.
Regards
Jukka