Help please!

OK, so the guy who wrote this Java program left after his contract was
up. My boss' bosses asked if I can look at it given I had one Java
course in college 6 years ago, making me their resident expert :0.  I
was given a link to a zip.

I'll call the zip and the directory I extracted it to x555. x555 has
subdirectories: doc, help, src, etc. src seems the most important, it
had another subdirectory in there called src and one called bin. the
lower src had subdirectories core, gui, bin, etc. in core is Nexus.java
and other .java files. Nexus.java has the main function. And to further
confuse things a perl file opens the actual thing and there are some
makefile files in a few of the places I mentioned, all of which has got
me overwhelmed.

The program had a readme saying to do this on the NT prompt:
  go to x555/src
  make
  make install
  make clean

  and "make build install clean" (i think) to get "a working build in
bin"

A new jar appears in the x555/src/src/bin

Then it says in the readme the program works only in UNIX.

My confusion comes in at this point. the command javac does not work on
NT!? java -version tells me 1.4.2 is on, yet javac gets me a command
not found message. On UNIX I can use javac, but the version there is
apparently 1.3. When I asked, the guy who gave me the link said the guy
who left used some java IDE but he didn't know which one.

Tutorials on the web always give a one java class example, which isn't
helping me too much. And oh yeah, when I did echo $CLASSPATH I think I
got nothing returned.

What my bosses want is to simply see if it is even possible to do a
simple change, then compile it successfully, and I am not succeeding at
this.

Can anyone give me some instructions please? Or point me to someplace
that has step by step instructions on how to compile this multipart
program?

If you got this far, thanks for reading and feel free to ask
questions...

russellmz