Portal - SSO server response not populated

unknown

We get these messages from time to time from portal users. Nothing consistent that I can locate.
I know we are behind on upgrade but Is there a way or can you tell me what this might be?
I hear, bookmarks, I hear batch jobs, but....
SSO server response not populated
details.
/servlet/Router/Transaction/Erp
SSORequest() - sso.js
(UNIX AIX 6.1) LCT 9.0.1.8 MSP6.