エラー発生！！！！

名前: 物理好き
日時: 2003-04-25 22:24:52
IPアドレス: 219.112.197.*

This is GUI-Shell Version 1.32, Copyright(C) 1996-1999 by Yoshiki OTOBE.
All rights reserved.
GUI-Shell Message(executing command): platex.exe a.tex

This is pTeX, Version p2.1.8, based on TeX, Version 3.14159 (SJIS) (Web2C 7.2)
(a.tex
pLaTeX2e <1998/09/01>+1 (based on LaTeX2e <1998/06/01> patch level 0)
(c:/ptex/texmf/tex/platex/base/jarticle.cls
Document Class: jarticle 1998/12/24 v1.1o Standard pLaTeX class
(c:/ptex/texmf/tex/platex/base/jsize10.clo))
(c:/ptex/texmf/tex/latex/graphics/pstcol.sty

! LaTeX Error: File `pstricks.sty' not found.

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

Enter file name: 
というエラーが出てしまいました！対処方法おしえて下さい

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