If you are using OpenOffice in headless mode, in time it's using more memory (memory leaking). As a solution I downloaded a loadbalancing application (XR http://crossroads.e-tunity.com/index.xr)
I started several OpenOffice instances, and if one of them consumes too much memory, I killed this instance and restarts is. With XR the end-users can still generated the documents, because an other OO-instance is used.
For best results, use the Firefox browser..