Scanning Windows 98 Machines

Hi,

We have quite a number of Windows 98 machines but SD+ is not able to scan any of them. I've tried to use the guide posted in other thread (http://forums.manageengine.com/forumHome.do?forumGroupId=49000000002007&forumTopicId=49000002688799) but it still doesn't work.
Whenever I tried to scan Windows 98 machine, I got Error 500 status.
Here is the detail error message:

----------------------------------------------------------------------------------------------
HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: null
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:545)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:486)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
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.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
com.adventnet.servicedesk.filter.EncodingFilter.doFilter(EncodingFilter.java:92)
com.adventnet.authentication.ContextChangeDetector.doFilter(ContextChangeDetector.java:113)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:75)

root cause

java.lang.NumberFormatException: null
java.lang.Long.parseLong(Unknown Source)
java.lang.Long.<init>(Unknown Source)
com.adventnet.servicedesk.asset.action.ViewWSDetailsAction.execute(ViewWSDetailsAction.java:48)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
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.doPost(ActionServlet.java:525)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
com.adventnet.servicedesk.filter.EncodingFilter.doFilter(EncodingFilter.java:92)
com.adventnet.authentication.ContextChangeDetector.doFilter(ContextChangeDetector.java:113)
org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:75)

note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.
Apache Tomcat/5.0.28
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Could anybody advise what causes this error and how we can successfully scan Windows 98 machines?

Thanks for your kind help in this.

Best regards,
Benny