Problem with add a component to monitoring - Java from rz21

Hello all,

I want to add a SAP portal NW 7.3 system in our CCMS solution manager based on NW 7.1

When I try to add java component to monitoring from RZ21. I get this error:

No valid XML document received. ( http://portal:50100/msgserver/xml/logon )

I did use correcet OS user (sid)adm and password.

The url http://portal:50100/ is from portal.

When I try to open the URL which appears in the error message:
"http://portal:50100/msgserver/xml/logon"

I get this  massage:

404   Not Found
  SAP NetWeaver Application Server 

  Error: Requested resource does not exist.

  SAP Technology Troubleshooting Guide

Details: Go to main page of this application.

I have not any problem to add abap and dual stack in CCMS I only have have problem with java stack.

Thanks for any advice.