This problem related with Internet Explorer.
It doesn't evaluate any more than 30 style elements.
Is it possible for richfaces to externalize these styles in a style sheet file?
So it looks like it is an IE problem, where it can only load 30 style tags or style sheet links. I think this is a problem for anyone creating a large page (i.e. a page with lots of richfaces components).
To get around this problem, I've create a custom renderer for the ScrollableDataTable, that overrides the renderStyle() method - it now stores the contents of the style tags in a buffer, that is rendered in a JSP. So now my template includes a link to the generated CSS JSP containing the styles generated by each scrollable data table.
Using the Microsoft Script Debugger, I tracked the problem down to line 232 in GridBody.js:
this.scrollBox.element.scrollTop = scrollTop;
It appears that this.scrollBox.element.scrollTop has not been defined, and when an assignment is attempted, it throws the above error.