Charts blow up at random XI 4.0

In webi documents with a dozen or more charts, the charts "blow up", or disappear for no apparent reason. Usually it happens while formatting a chart; when clicking OK to execute the changing of one or more settings in a chart, ALL the charts in all the reports in the document go blank, with the red X error indicator on every chart.

This happens also when making selections using an input control while in design mode.

The only consistent recovery I know of is to save the document, then log out of B-O, log back in and reload the document. The charts are nearly always displayed upon reloading.

It is worth noting that while using our installation of B-O we encounter many instances per day where the web intelligence/java engine simply hangs while loading, returns an error when reloading a document, or java will load but hang when actually loading the document. Together with reloading documents to see and/or work with the charts, this means a minimum of two or more hours per day of waiting for something to load or re-load.

Any suggestions would be welcome.

Thanks,

Bryan