To get the extension working properly, you have to configure the .htaccess file in the typo3 root else the shop will never show correctly.

Edit the file and add after : 'RewriteEngine On' the following line:

RewriteRule catalog/(.*) /typo3conf/ext/meta_oscommerce/mod1/oscommerce/$1   [L]

Where catalog is the virtual directory where the shop will be accessible.

Important : In all the shop installation when it ask the shop home you must set you « catalog » directory.