For Bash-compatible shells, you're supposed to use ". settings32.sh" (a dot instead of "source") but anyway...
Check out this thread:
Installation of ISE 13.2 on Ubuntu Linux (I have replied in there as well)
Also there's a number of other threads on Xilinx user forum in
Installation and Licensing section - some may be about different ISE / Ubuntu versions or other Linux distro's, but still be helpful in fixing the problem.
Btw: location in /media suggests that it's an external (removable?) drive? If so, it's possible medium is mounted with "noexec" option meaning you can't run executables/scripts from that drive directly. In a terminal, do "mount" and check options for relevant drive to see if that's the case. If so, you can use /etc/fstab to mount device with appropriate options, or install ISE on main drive (usually under /opt, or in your home directory). And the filesystem type itself could be an issue - what filesystem is that disk (with ISE on it) using?
Oh and chmod 777 is generally a bad idea: that way
any user on your system can read
and write to that file, including perhaps some process that deals with remote systems. chmod 755 is more sane permissions for files that are only meant to be read & executed.
:!: For what it's worth: Ubuntu 11.04 isn't the best platform for development software like ISE suite. I've tried it myself for about a week, then wiped it because of many encountered bugs/issues (previous 10.x LTS releases were much more stable / polished). Debian (-stable, my preferred distro these days) / Fedora / CentOS / OpenSUSE might be better options to run ISE on.