Okiedokie people, Here are some solutions to a number of problems that I saw people having (myself included):

Alternate Ubuntu Directions for Step 5 above (from a mostly clean Hardy install):
1) You'll need gcc 3.4 (as mentioned)
2) Use synaptic or apt to get: 
 - cpp-3.4 
 - gcc-3.4 
 - gcc-3.4-base
3) Try to run configure.
4) If you see an error like "configure:1799: error: C compiler cannot create executables" then it's probably because you're missing some link libraries. Use synaptic/apt to get:
 - libc6-dev
4) Try to "make all" 
5) If you see an error like "HGraf.c:73:77: X11/Xlib.h: No such file or director", then you need:
 - libx11-dev
6) Now "make all" should succeed.

Hope that helps!
~PST

Some references:
- http://groups.google.com/group/emm-ruby/browse_thread/thread/d1b5dafeb6296d3d?pli=1
- http://anaaman.blogspot.com/2006/01/crt1o-no-such-file-no-such-file-or.html
- http://ubuntuforums.org/archive/index.php/t-49497.html