OpenDocument and java.lang.NullPointerException

Hi all, we are trying to call a report via openDocument URL managing the logon with a jsp page on BO XI 4.

We create in the JSP the logon token

//Create session token enterpriseSession = CrystalEnterprise.getSessionMgr() .logon(bo_username, bo_password, BO_CMS_NAME, BO_AUTH_TYPE);
 logonTokenMgr = enterpriseSession.getLogonTokenMgr(); 
defaultToken = logonTokenMgr.createLogonToken("",120,100); 
String tokenEncode = URLEncoder.encode(defaultToken, "UTF-8"); 
enterpriseSession.logoff();

Then we do the redirect ....

sDocNameStr = IDOCID_NAME_PARAMETER + "=" + "Ab3R7uNJ0F9Ot6Bg4mLhjaQ" +"&"+ IDOCTYPE_NAME_PARAMETER; 
bo_cms_url = BO_CMS_PROTOCOL + BO_CMS_NAME + ":"+ BO_CMS_PORT + "/" + BO_CMS_PATH + "?"+ sDocNameStr; 
response.sendRedirect(bo_cms_url + "&token="+tokenEncode);

But from the server we receive the following error : java.lang.NullPointerException (see the attachment IMG1) This is the output.println ...

http://....:8080/BOE/OpenDocument/opendoc/openDocument.jsp?iDocID=Ab3R7uNJ0F9Ot6Bg4mLhjaQ&sIDType=CUID&token=NTBO4.mgraf.lan%3A6400%40159550J3WZSJ8nZKK83NvOSPXy1Au159549JhE9R8Xi8HfDebq32OB6udo

Seems that the token is not valid or correct to open the report but if we open a CMC session then we are able to load the report (see the attachment IMG2)

May you help me?