Sure, this code works for me: http://pastebin.com/8C1i2EHW where reportUnitName is a valid report unit URI. Or, this version: http://pastebin.com/DmuHAv7F with timezone, start and end dates skipped works just fine too
Faced the same issue today. You need to use start date along with timezone (which should not be null and is to be set explicitly if startDate is specified). Or just omit timezone, start and end dates.