Missing *.sty and/or *.cls files?

[Virgil Stokes]

First, I am trying to get started with LyX (vers. 1.6.4) on a Ubuntu 
(vers. 9.10) platform. I am also very new with Ubuntu trying to migrate 
from Windows.

Second, your work on this package is impressive. It downloaded and 
installed very easily.

Third, I started by looking at some of your templates. Many of these 
would not "compile" --- gave a rather long error message in a window 
that was labeled

  LyX: Document class not available

I did look at Customization documentation as suggested in the error 
message in this window; however, I still could not understand how to fix 
the problem. Unfortunately, the error message does not give any 
information on what *.sty and/or *.cls files are missing. For example, 
when I tried the template elsarticle.lyx this error message came up. I 
then looked at this file in a text editor and saw

 \textclass elsarticle

But, it is not clear how this is related to the problem.

I would like to use your very interesting LyX package; but, I need some 
help on how to fix such problems. Note,

  Library directory: /usr/share/lyx/
  User directory: ~/.lyx

I would be glad to provide any additional information that you may need.

--V