I had a rough time trying to get my gallery2 install imported and moved to the gallery3 platform. The g2 import process stalled out a lot and crashed & burned hard when faced with different folder names for the redirects (/gallery became /photos). After a lot of fighting with the g2import module & htaccess, I disabled the g2import module and pursued a strictly .htacccess solution for redirecting visitors from the old gallery2 URL to the new gallery3 URL.