about error

Hi,

When I was testing a servlet  with the Jigsaw server it informed an error. 
I have the servlet.jar at the Jigsaw's CLASSPATH.
I don't understand why this error. 

Thanks for any contribution,


java.lang.NoClassDefFoundError: javax/servlet/http/HttpServletRequest
        at com.oreilly.servlet.multipart.MultipartParser.<init>(MultipartParser.
java:103)
        at com.oreilly.servlet.multipart.MultipartParser.<init>(MultipartParser.
java:83)
        at com.oreilly.servlet.MultipartRequest.<init>(MultipartRequest.java:117
)
        at UploadTest.doPost(UploadTest.java:23)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:747)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:840)
        at org.w3c.jigsaw.servlet.ServletWrapper$ServletRunner.run(ServletWrapper.java:290)

**************************************************************
PhD Student Rolf Fredi Molz                                     
UNISC - University of Santa Cruz do Sul - RS/ Brazil
Phone: +55 (51) 717 7393
E-mail : rolf@dinf.unisc.br
**************************************************************