TeX初心者です。美文書作成入門第五版の22ページの文章を打ち込んだところ、以下のようなエラーが出てしまいました。
This is pTeX, Version 3.1415926-p3.1.11 (utf8.sjis) (Web2C 2010)
restricted \write18 enabled.
(./ex1.tex
pLaTeX2e <2006/11/10>+0 (based on LaTeX2e <2009/09/24> patch level 0)
Babel and hyphenation patterns for english, afrikaans, ancientgreek, ib
ycus, arabic, armenian, basque, bulgarian, catalan, pinyin, coptic, croatian, c
zech, danish, dutch, ukenglish, usenglishmax, esperanto, estonian, ethiopic, fa
rsi, finnish, french, galician, german, ngerman, swissgerman, monogreek, greek,
hungarian, icelandic, assamese, bengali, gujarati, hindi, kannada, malayalam,
marathi, oriya, panjabi, tamil, telugu, indonesian, interlingua, irish, italian
, kurmanji, lao, latin, latvian, lithuanian, mongolian, mongolianlmc, bokmal, n
ynorsk, polish, portuguese, romanian, russian, sanskrit, serbian, slovak, slove
nian, spanish, swedish, turkish, turkmen, ukrainian, uppersorbian, welsh, dumyl
ang, nohyphenation, loaded.
! LaTeX Error: File `jsarticle.cls' not found.
Type X to quit or to proceed,
or enter new name. (Default extension: cls)
Enter file name:
documentclassがarticleの時には、出力できます。また、jsarticle.clsもC:\w32tex\share\texmf\tex\platex\jsにあります。
どうしたら解決しますか？教えてください。よろしくお願いします。