Redmine

Hello,
I'm trying to install the plugin : "redmine_custom_workflow" from this page [[http://www.redmine.org/plugins/custom-workflows]] but I get the following error:

rake aborted!
An error has occurred, all later migrations canceled:

Mysql2::Error: BLOB/TEXT column 'description' can't have a default value: ALTER
TABLE `custom_workflows` CHANGE `description` `description` text DEFAULT '' NOT
NULLC:/web/redmine_2.3.0/plugins/redmine_custom_workflows/db/migrate/20120628060
102_change_custom_workflows_description_type.rb:3:in `up'
C:in `migrate'
C:/web/redmine_2.3.0/lib/redmine/plugin.rb:453:in `migrate_plugin'
C:/web/redmine_2.3.0/lib/redmine/plugin.rb:425:in `migrate'
C:/web/redmine_2.3.0/lib/redmine/plugin.rb:439:in `block in migrate'
C:/web/redmine_2.3.0/lib/redmine/plugin.rb:438:in `each'
C:/web/redmine_2.3.0/lib/redmine/plugin.rb:438:in `migrate'
C:/web/redmine_2.3.0/lib/tasks/redmine.rake:74:in `block (3 levels) in <top

Any idea about this ?