I'm very new to this stuff, only done basic html before...

I've installed mamp version 1.4.1 to be compatible with my old mac but I'm having trouble at the install stage, I'm at
http://localhost:8888/silverstripe/install.php

Under MySQL Database I get a message saying:
These database details don't appear to be correct. Please enter the correct details before installing.

These are the default details (not sure what to change them to or how to change them):

MySQL server: localhost
MySQL username: root
MySQL password:
MySQL database: ss_mysite

The only other thing that's in orange is below (but I checked the php file and it looks set to 64M):
Memory allocated (PHP config option 'memory_limit')   SilverStripe needs a minimum of 32M allocated to PHP, but recommends 64M. We can't determine how much memory you have allocated. Install only if you're sure you've allocated at least 20 MB.

If anyone could help get me past this hiccup I'd be very grateful!