[EC-CUBE]2.12.4
[レンタルサーバー]XREA
[PHP]5.2.9
[データベース]MySQL5.0.77

この度ECCUBEを初めて利用する事になり、インストールまでは完了しましたが、管理画面にログインしようとすると真っ白の画面になり、****/admin/?　というURLになります。
管理画面以外は正常に機能しているようです。(TOPページ等)

data/logsの中のerror.logを見ると良いというのを見かけましたので、ログインしようとした際に吐き出されていたエラーログを記載致します。

インストール時にこちらで操作した点と言えば、html/define.phpの
3行目をdefine('HTML2DATA_DIR', '/data/');
に変更
ドメイン直下にインストールしたかった為、htmlフォルダの中身とdataをルートディレクトリにアップロード

くらいだと思います。
パーミッションエラーは大量に出ましたが、特定フォルダのみFFFTPの転送3の設定で666にしてアップロードしました。

// エラーログ
[/admin/index.php] Warning(E_WARNING): session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cookie - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/sessionfactory/SC_SessionFactory_UseCookie.php(55)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cache limiter - headers already sent (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/sessionfactory/SC_SessionFactory_UseCookie.php(55)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): Cannot modify header information - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/pages/LC_Page.php(340)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): Cannot modify header information - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/pages/LC_Page.php(341)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): Cannot modify header information - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/pages/LC_Page.php(342)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): Cannot modify header information - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/pages/LC_Page.php(343)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): session_start() [<a href='function.session-start'>function.session-start</a>]: Cannot send session cache limiter - headers already sent (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/sessionfactory/SC_SessionFactory_UseCookie.php(55)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): Cannot modify header information - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/pages/LC_Page.php(340)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): Cannot modify header information - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/pages/LC_Page.php(341)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): Cannot modify header information - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/pages/LC_Page.php(342)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): Cannot modify header information - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/pages/LC_Page.php(343)] from ***.***.***.***
[/admin/index.php] Warning(E_WARNING): Cannot modify header information - headers already sent by (output started at /home/****/public_html/define.php:1) on [/home/****/public_html/data/class/SC_Response.php(206)] from ***.***.***.***


お手数ですが、ほとんど素人ですのでお詳しい方助けていただけますとうれしいです！！何卒よろしくお願い致します。