Suppress author leaves a leading comma before the year in APA format. e.g. (, 2005). The format should be year only, e.g. (2005). As far as I know, only multiple references for the same author use the ", yyyy" format, e.g. (Smith 1994, 1995a, 1995b, 2000; Jones 1988).

Zotero 1.0.0rc5 openoffice extension1.0b1, firefox 2.0.0.5, ubuntu linux 7.04