kazumasa99　さん

教えていただいたとおり、sudo mktexlsr　とやってみましたが、
やはり同様のエラーがでてしまいました。
念のため、その時のエラーも載せておきます。

This is pdfTeXk, Version 3.141592-1.40.3 (Web2C 7.5.6) (format=latex 2008.8.22)  23 NOV 2008 18:40
entering extended mode
%&-line parsing enabled.
**\nonstopmode\input ex3.tex
(./ex3.tex

! LaTeX Error: File `jsarticle.cls' not found.

Type X to quit or <RETURN> to proceed,
or enter new name. (Default extension: cls)

Enter file name:
! Emergency stop.
<read *>
         
l.2 \begin
          {document}^^M
*** (cannot \read from terminal in nonstop modes)


Here is how much of TeX's memory you used:
10 strings out of 95087
188 string characters out of 1183278
45034 words of memory out of 1500000
3280 multiletter control sequences out of 10000+50000
3640 words of font info for 14 fonts, out of 1200000 for 2000
28 hyphenation exceptions out of 8191
10i,0n,7p,64b,8s stack positions out of 5000i,500n,6000p,200000b,5000s
No pages of output.

toshio　さん

確かに、言っていただいたようにすると、以下のようになりました。ですが、
dviファイルは出来上がってもやはり日本語が表示されません。

どうやら文字がないようです。自分でも調べて見ますが、どのようにすればよいか
お返事をいただけると、とても助かります。

（ちなみにコンパイルしたのは

\documentclass{jsarticle}
\begin{document}
confirming english desplayed.
日本語の確認。
\end{document}

です。）

This is pTeXk, Version 3.141592-p3.1.10 (euc) (Web2C 7.5.4) (format=platex 2008.8.22)  23 NOV 2008 19:50
%&-line parsing enabled.
**ex3
(./ex3.tex
pLaTeX2e <2006/11/10>+0 (based on LaTeX2e <2005/12/01> patch level 0)
(/usr/share/texmf/ptex/platex/misc/jsarticle.cls
Document Class: jsarticle 2007/10/24 okumura
LaTeX Info: Redefining \rmfamily on input line 319.
LaTeX Info: Redefining \sffamily on input line 322.
LaTeX Info: Redefining \ttfamily on input line 325.
\symmincho=\mathgroup4
LaTeX Font Info:    Overwriting symbol font `mincho' in version `bold'
(Font)                  JY1/mc/m/n --> JY1/gt/m/n on input line 390.
LaTeX Font Info:    Font shape `JT1/mc/m/n' will be
(Font)              scaled to size 9.60999pt on input line 582.
LaTeX Font Info:    Font shape `JY1/mc/m/n' will be
(Font)              scaled to size 9.60999pt on input line 582.
\fullwidth=\dimen118
LaTeX Font Info:    Font shape `JT1/mc/m/n' will be
(Font)              scaled to size 7.68799pt on input line 729.
LaTeX Font Info:    Font shape `JY1/mc/m/n' will be
(Font)              scaled to size 7.68799pt on input line 729.
\c@part=\count81
\c@section=\count82
\c@subsection=\count83
\c@subsubsection=\count84
\c@paragraph=\count85
\c@subparagraph=\count86
\@abstractbox=\box41
\c@figure=\count87
\c@table=\count88
\abovecaptionskip=\skip41
\belowcaptionskip=\skip42
\@lnumwidth=\dimen119
\bibindent=\dimen120
LaTeX Info: Redefining \TeX on input line 1682.
LaTeX Info: Redefining \LaTeX on input line 1708.
LaTeX Info: Redefining \LaTeXe on input line 1733.
\heisei=\count89
)
No file ex3.aux.
\openout1 = `ex3.aux'.

LaTeX Font Info:    Checking defaults for OML/cmm/m/it on input line 2.
LaTeX Font Info:    ... okay on input line 2.
LaTeX Font Info:    Checking defaults for T1/cmr/m/n on input line 2.
LaTeX Font Info:    ... okay on input line 2.
LaTeX Font Info:    Checking defaults for OT1/cmr/m/n on input line 2.
LaTeX Font Info:    ... okay on input line 2.
LaTeX Font Info:    Checking defaults for OMS/cmsy/m/n on input line 2.
LaTeX Font Info:    ... okay on input line 2.
LaTeX Font Info:    Checking defaults for OMX/cmex/m/n on input line 2.
LaTeX Font Info:    ... okay on input line 2.
LaTeX Font Info:    Checking defaults for U/cmr/m/n on input line 2.
LaTeX Font Info:    ... okay on input line 2.
LaTeX Font Info:    Checking defaults for JY1/mc/m/n on input line 2.
LaTeX Font Info:    ... okay on input line 2.
LaTeX Font Info:    Checking defaults for JT1/mc/m/n on input line 2.
LaTeX Font Info:    ... okay on input line 2.
Missing character: There is no ^^e6 in font cmr10!
Missing character: There is no ^^97 in font cmr10!
Missing character: There is no ^^9c in font cmr10!
Missing character: There is no ^^aa in font cmr10!
Missing character: There is no ^^9e in font cmr10!
Missing character: There is no ^^e3 in font cmr10!
Missing character: There is no ^^81 in font cmr10!
Missing character: There is no ^^8d in font cmr10!
Missing character: There is no ^^e3 in font cmr10!
Missing character: There is no ^^80 in font cmr10!
Missing character: There is no ^^82 in font cmr10!
[1

] (./ex3.aux) )
Here is how much of TeX's memory you used:
360 strings out of 95531
3463 string characters out of 1191153
51758 words of memory out of 1500000
3604 multiletter control sequences out of 10000+50000
8372 words of font info for 36 fonts, out of 1200000 for 2000
19 hyphenation exceptions out of 8191
23i,4n,19p,123b,246s stack positions out of 5000i,500n,6000p,200000b,5000s

Output written on ex3.dvi (1 page, 308 bytes).

>>kazumasa99さん、 toshioさん

http://forum.ubuntulinux.jp/viewtopic.php?id=1941

を参照することで、表示の問題は解決しました。
助けていただいてありがとうございました。