rake migrations with namespace (prefix)

I have access to a shared database. So, I wanted to create my
application tables with a prefix "cmro_". So, I did this:
1. I edited config/environment.rb and added this line:
config.active_record.table_name_prefix = 'cmro_'
2. I ran rake db:migrate. But I kept getting errors (pasted below).
Any suggestions on how to fix these?
3. I am also not sure how to clean the database again. Is there some
sort of rake db:destroy to clean-up all the tables that rake created?

*************FIRST ATTEMPT************
bash-3.00$ rake db:migrate
(in /work/storage/ror1-workdir/cmro)
== CreateTemplates: migrating