So far I haven't been able to reproduce your issue. This is what I've done:
- Install Mantis 1.2.19 and create a project.
- Install Mantis 2.21.0 on a different location.
- Remove the
/opt/bitnami/mantis-2.21.0-0/mysql/data/bitnami_mantis folder that contains the Mantis 2 database
- Copy the
/opt/bitnami/mantis-1.2.19-0/mysql/data/bitnami_mantis folder that contains the Mantis 1 database to
Doing this, I am able to login to my Mantis 2.21 installation. Could you please describe all the steps you took in order for me to reproduce your issue? You talk about copying "the database" folder, which folder are you referring too?
On another note, you may want to try downloading the
admin/install.php so you can execute it, since the Mantis installation removes it. You can download Mantis 2.21.0 from here, then you can get the
admin/install.php file from the zip and put it on your Mantis installation.