When migrating a Wordpress instalation some things could go wrong.
If you changed the table prefix, you might be getting this error when logging in the wordpress admin:
You do not have sufficient permissions to access this page
Open phpmyadmin or something like that and go through the values in tables:
find values that start with the old prefix, for example wp_ and change it to the new prefix.
wp_usermeta I changed all meta_key values from wp_* to newprefix_*
wp_options I changed wp_user_roles to newprefix_user_roles.