The latest Bricscad Linux V10.4.9 Beta was released almost a month ago, on June 22nd. As with previous Beta releases, a Debian *.deb package is available for Debian/Ubuntu and derivative operating systems.
The thing is, even though V10.4.9 apparently installs without problem on 64-bit systems, the software won't start. When launched from a terminal, the error message is as follows:
exec: 3: /opt/bricsys/bricscad/v10/bricscad: not found
And even if the Bricscad (Linux) Beta release notes acknowledge the problem, they don't provide a solution:
Installation issues on 64 bit. It is possible to run Bricscad (Linux) on a 64 bit system. However, the Bricscad (Linux) installers do not automatically all required 32 bit libraries. Additional manual setup is needed. We aim to fix and/or document flaws in the installers as soon as possible.
So after some exchange with my fellow users on the Bricsys support forums, I was finally able to run Bricscad on Ubuntu 10.04 64-bit.
The solution
You just need to install the ia32-libs shared libraries. (Click on the link to instantly install the libraries, provided the apturl protocol is installed on your system, and your browser supports it.)