お世話になります。
以下の EC-CUBE 2.11.5 環境で、管理画面＞商品管理＞商品登録CSV で、72項目のカテゴリIDを空欄にしてアップロードを行った場合、
システムエラーが発生し、以下のようなエラー文が出力されます。
開発コミュニティ＆チケットにも見当たらなかったようなので、投稿しました。
よろしくお願いします。

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エラー文（data/logs/site.log)
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USER_AGENT: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.152 Safari/535.19

SQL: INSERT INTO dtb_product_categories(category_id,product_id,rank) VALUES ($1,$2,$3)

PlaceHolder: array (
0 => '',
1 => 7,
2 => 1,
)

MDB2 Error: null value violates not-null constraint

_doQuery: [Error message: Could not execute statement]
[Last executed query: EXECUTE mdb2_statement_pgsql_10b530bc4d5992d01ec47eaa0943acaa150e6823c5 (NULL, 7, 1)]
[Native message: ERROR: null value in column "category_id" violates not-null constraint]

/var/www/html/sample.com/public_html/html/admin/products/upload_csv.php 34:LC_Page_Admin_Products_UploadCSV_Ex->process
/var/www/html/sample.com/public_html/data/class_extends/page_extends/admin/products/LC_Page_Admin_Products_UploadCSV_Ex.php 56:LC_Page_Admin_Products_UploadCSV->process
/var/www/html/sample.com/public_html/data/class/pages/admin/products/LC_Page_Admin_Products_UploadCSV.php 90:LC_Page_Admin_Products_UploadCSV->action
/var/www/html/sample.com/public_html/data/class/pages/admin/products/LC_Page_Admin_Products_UploadCSV.php 129:LC_Page_Admin_Products_UploadCSV->doUploadCsv
/var/www/html/sample.com/public_html/data/class/pages/admin/products/LC_Page_Admin_Products_UploadCSV.php 246:LC_Page_Admin_Products_UploadCSV->lfRegistPoduct
/var/www/html/sample.com/public_html/data/class/pages/admin/products/LC_Page_Admin_Products_UploadCSV.php 419:SC_Helper_DB->updateProductCategories
/var/www/html/sample.com/public_html/data/class/helper/SC_Helper_DB.php 630:SC_Helper_DB->addProductBeforCategories
/var/www/html/sample.com/public_html/data/class/helper/SC_Helper_DB.php 555:SC_Query->insert
/var/www/html/sample.com/public_html/data/class/SC_Query.php 484:SC_Query->query
/var/www/html/sample.com/public_html/data/class/SC_Query.php 741:SC_Query->execute
/var/www/html/sample.com/public_html/data/class/SC_Query.php 894:MDB2_Statement_Common->execute
/var/www/html/sample.com/public_html/data/module/MDB2.php 4152:MDB2_Statement_pgsql->_execute
/var/www/html/sample.com/public_html/data/module/MDB2/Driver/pgsql.php 1474:MDB2_Driver_pgsql->_doQuery
/var/www/html/sample.com/public_html/data/module/MDB2/Driver/pgsql.php 673:MDB2_Driver_Common->raiseError
/var/www/html/sample.com/public_html/data/module/MDB2.php 1497:PEAR->raiseError
/var/www/html/sample.com/public_html/data/module/PEAR.php 557:MDB2_Error->MDB2_Error
/var/www/html/sample.com/public_html/data/module/MDB2.php 1009:PEAR_Error->PEAR_Error
from xxx.xxx.xxx.xxx

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システム情報概要
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EC-CUBE 2.11.5
サーバーOS Linux xxxxxxx.com 2.6.18-194.26.1.el5 #1 SMP Tue Nov 9 12:54:20 EST 2010 x86_64
DBサーバー PostgreSQL 9.0.4
WEBサーバー Apache/2.2.3 (CentOS)
PHP 5.3.10 (Core, date, ereg, libxml, openssl, pcre, zlib, bz2, calendar, ctype, hash, filter, ftp, gettext, gmp, SPL, iconv, Reflection, session, standard, shmop, SimpleXML, sockets, exif, tokenizer, xml, apache2handler, OAuth, apc, curl, dom, fileinfo, gd, json, mbstring, mcrypt, mysql, mysqli, PDO, pdo_mysql, pdo_pgsql, pdo_sqlite, pgsql, Phar, wddx, xmlreader, xmlwriter, xsl, zip, mhash)
GD 有効 (GD Version => bundled (2.0.34 compatible), FreeType Support => 1, FreeType Linkage => with freetype, T1Lib Support => 1, GIF Read Support => 1, GIF Create Support => 1, JPEG Support => 1, PNG Support => 1, WBMP Support => 1, XPM Support => 1, XBM Support => 1, JIS-mapped Japanese Font Support => )
HTTPユーザーエージェント Mozilla/5.0 (Windows NT 5.1) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.152 Safari/535.19
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