In case you want to upgrade to magento 1.4, and have Yoast MetaRobots installed, you'll have to uninstall it first, since it's not compatible with 1.4.
1. uninstall it from magento connect
2. Remove the config xml file from /app/etc/modules/Yoast_Metarobots.xml
3. Remove the module files and directories from /app/code/community/yoast/Metarobots/
4.Clear your cache
SSH into your root magento directory and:
rm -rf var/cache/*
5. run this SQL query (easily done in phpMyAdmin)
DELETE FROM `eav_attribute` WHERE `eav_attribute`.`attribute_code` = 'meta_robots';
DELETE FROM `core_resource` WHERE CODE = 'metarobots_setup';
You should be good to go after this...