I also run Win 98SE and had problems with KB891711 as it runs in the Start-up file.
Go to Start/ RUN type msconfig in the box and click OK.
Go to the Start tab and remove the tick from KB891711 and see if it cures the problem.
I removed this update altogether and have never replaced it. System now runs normal.
I have had the other update (888113) installed since March 2005 with no problems so I assume this one is OK.