Hello Javier, and others,
I believe that was the right password, but I'm now a bit at a loss as to how the mysqldump will get working.
Yesterday I tried this several times and though using the password found in database.yml seemed to work (along with user 'bitnami'), the mysqldump statement was accepted, but then the system would seem to just stall (I waited the whole night, and though my repository is not that big, it didn't finish execution). Now after re-booting the computer, it is giving me the 1045 error (Access denied for user 'bitnami'@'localhost'...). Very strange, I did notice however that using the bitnami user and the password from database.yml, I can get into the mysql shell with:
mysql -u bitnami -p bitnami_redmine
So, that would suggest that the password is correct, there is something blocking me from doing the dump. Sorry for my inexperience here, but I seem to be following instructions, just can't get anywhere.