NoClassDefFoundError after compiling

I'm using jawin with a web application under Tomcat 5.0.

Everything works fine except when I compile , i get:

java.lang.NoClassDefFoundError
 com.develop.jawin.IdentityManager.registerProxy(Unknown Source)
 com.develop.jawin.UnknownPtr.(Unknown Source)
 com.itechnology.canalfutbol.beans.OLAPConnectionFactory.getOLAPConne
ction(OLAPConnectionFactory.java:23)
 org.apache.jsp.site.ranking_005findividual_005favanzado_jsp._jspServ
ice(ranking_005findividual_005favanzado_jsp.java:295)
 org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
 org.apache.jasper.servlet.JspServletWrapper.service
(JspServletWrapper.java:311)
 org.apache.jasper.servlet.JspServlet.serviceJspFile
(JspServlet.java:301)
 org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
 org.apache.struts.action.RequestProcessor.doForward
(RequestProcessor.java:1069)
 org.apache.struts.action.RequestProcessor.processForwardConfig
(RequestProcessor.java:455)
 org.apache.struts.action.RequestProcessor.process
(RequestProcessor.java:279)
 org.apache.struts.action.ActionServlet.process
(ActionServlet.java:1482)
 org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:507)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:743)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
 com.itechnology.canalfutbol.filters.RequestFilter.doFilter
(RequestFilter.java:56)

When i restart the tomcat server it is fixed.
My jawin.jar and jawin.dll files are in the WEB-INF/lib forder.

Thanks in advance.