How?

I followed directions from site and I get this error message:

E: Couldn't find package ymessenger_1.0.4_1_i386

This is where I'm at and what I'm doing:

root@Knoppix:/home/Ryan# apt-get install ymessenger_1.0.4_1_i386
Reading Package Lists... Done
Building Dependency Tree... Done
E: Couldn't find package ymessenger_1.0.4_1_i386

Anything else to try?