installing on linux

New to Linux and trying to install with the terminal. I followed the directions here for the RPM install (http://java.sun.com/j2se/1.5.0/jre/install-linux.html). Once I run the command,

sudo ./jre-1_5_0_11-linux-i586-rpm.bin

I get this...

replace jre-1_5_0_11-linux-i586.rpm? [y]es, [n]o, [A]ll, [N]one, [r]ename: A

inflating: jre-1_5_0_11-linux-i586.rpm

./jre-1_5_0_11-linux-i586-rpm.bin: 644: rpm: not found

Any ideas. I'm running Ubuntu.

[488 byte] By [prem1ersa] at [2007-11-27 4:50:23]