Using this URL to run a report: http://MyServer/ReportServer/Pages/ReportViewer.aspx?/UsageReports/MyReport/ &rs:Command=Render&rs:Format=Excel&ProductDisplayName=[Product].[Display Name].&[ABC]&CalendarYearWeekDate=Mon, Jan 1, 2007 issues this error: The path of the item '/UsageReports/MyReport/,[ABC]' is not valid. The full path must be less than 260 characters long; other restrictions apply. If the report server is in native mode, the path must start with slash. I'm not seeing what's wrong with that URL that it would cause that error to happen. I have used much larger URL paths to open reports with SQL parameters in SSRS, so could it be the MDX? I have also tried encoding prior to opening and still get same error. Thanks for any advice!--ACG

The answer is that the browser doesn't encode the extra ampersands in the MDX parameters. So I have to do it manually before sending url to browser.--ACG