All, I have been able to replicate this on three environments.  Creating a prompt page with any prompt on it will allow you to run it to HTML or PDF, but bombs out on exporting to Excel, CSV.  You get a DPR-ERR-2008 error.  Put the prompt directly above your list report on the Report Page, no problem.  The same error occurs if you create a prompt using the old CWA methods with a custom filter and checking the prompting box.  Go into the old Cognos Connection method, all works fine.
This is a rather large issue.  Anyone else experience this?
Thanks...............
			
			
			
				Made a test report specifically to try this and was able to duplicate it. Did you already open a PMR / APAR with IBM?