nulldc wont work,,

i have this nulldc,,
and a dump of crazy taxi and a dump of rez from my friend,,
im using beta 1.6,,
and when i try to load crazy taxi on 1.6,,
it just goes to a white screen,,
also rez acts like that,,
and when i tried 1.3,,
crazy taxi is so slow..
and rez wont work,,
so i downloaded Crazy taxi(i have my copy, i just dont have my dreamcast),,
and it also wont work,,
i also downloaded Rez(an echelon release),,
it just starts with a white screen and plays the echelon intro music,,
and when i press start,,
it just stay on the white screen,,
any suggestion to fix this?,,
im using the nullpvr plugin for bothe 1.6 and 1.3,,
any help would be appreciated,,