"platex command not found" in yatex-mode after C-c tj.

[Gerry Butler]

I am starting to use emacs to edit latex (.tex) files in yatex-mode on 
Debian/linux. 

When I enter C-c tj (which I think should run latex to generate a .dvi), I 
receive a message "/bin/bash: platex: command not found". 

I'm a bit new to emacs, linux, and latex, so I don't know where to look next. 

The Debian installation has automatically setup emacs so that it enters yatex 
mode when it opens a .tex file, so I imagine platex (or whatever else it needs) 
should be available. 

If I switch emacs to latex-mode, then use C-c C-f, then the .dvi is generated 
with no problem.

Thank you

Gerry