need help going from fresh 1.1 to toast v2.1

my phone is version 1.56, does that matter? Do I need to update the base first then flash the new rom or should I be able to wipe and flash? I'm pretty sure the update from 1.56 to 2.1 is included in the ROM but since this isnt working there must be something i'm missing. From what I've read it should be as simple as Wipe data/factory reset, Wipe Dalvik-Cache, Wipe SD:ext partition, Flash zip from sdcard, select Fresh-Toast......Reboot....Done.... But its not working and it should.