Can’t login to new site even after resetting password

I’m redeveloping a site for a client. I’ve duplicated the site and database, changed the wp-config.php and wp_options table to reflect the new URL I’m testing with.

I’m now having problems gaining admin access. I added a new user to the table through phpMyAdmin and could log in fine, but when I tried changing the admin password (I don’t know the original) it gives me an ‘incorrect password’ error. I tried resetting it through the emergency.php password changer script – same error. I’m 99.9% sure that the password has been changed – I created an MD5 hash of my password and updated the table with it, which definitely worked, and I’m positive I’m typing it right. Before I changed the wp_options table I had some issues with redirection to the old site, although that seems to have stopped. Is there any other code/setting anywhere that could be messing this up?

Thanks
Matt