AmiQuote is essentially web browser, but specialized in downloading data from public web sources. It does not perform any calculations. It just downloads quotes that are available on the web site. If web site does not perform dividend adjustments (like Yahoo now), AmiQuote won't do that for you. It also does not download dividend data because dividend data are not available in the "Download Data" link.
For more information see http://www.amibroker.com/kb/2007/08/04/amiquote-and-free-data-from-yahoo/