Redmine

I try to install redmine_impasse (http://kawasima.github.io/redmine_impasse/administration_guide.html)

I got "rake aborted! database configuration does not specify adapter" 

after i input "rake db:migrate_plugins"

then I found the plugin document in here (http://www.redmine.org/projects/redmine/wiki/Plugins)

and input "rake redmine:plugins:migrate RAILS_ENV=production"
I still got some error message like

"rake aborted!
An error has occurred, all later migrations canceled" <= I didn't use --trace so it didn't show any useful message.

It seems work at beginning... I saw option from the plugin show up in the GUI,
But It made the project that use the plugin just become Internal Error (500 error) (in admin > project > one of project >setting > module> checked the plug-in option (test management))
Now I can't check the setting of the project.

I tried to check the database.yml in the config folder but the adapter setting is correct (there is a space in front of mysql)
and I check production.log too. but I just the system was migrating.. no error message.
Really dont know how to fix the 500 error page. So I decide to remove the plugin...
by using this ->sudo rake redmine:plugins:migrate NAME=redmine_impasse VERSION=0 RAILS_ENV=production
this was the error msg:

 drop_table(:impasse_requirement_issues)
rake aborted!
An error has occurred, all later migrations canceled:

Mysql::Error: Unknown table 'impasse_requirement_issues': DROP TABLE `impasse_requirement_issues`
Tasks: TOP => redmine:plugins:migrate

is there any ppl know how to remove it or install it correctly?
Information about my environment
DB mysql
server apache2
Remine 2.3.3

I know nothing about ruby...really need help here