At this point, the next menu item presented should be ``Initialize a Linux Partition.'' If it isn't, either you haven't completed the disk partitioning process, or you haven't made one of the menu choices dealing with your swap partition.
You can initialize a Linux partition, or alternately you can mount a previously initialized one. Note that dbootstrap will not upgrade an old system without destroying it. If you're upgrading, Debian can usually upgrade itself, and you won't need to use dbootstrap. The Debian 2.1 release notes contain upgrade instructions.
If you are using old disk partitions that are not empty, i.e., if you want to just throw away what is on them, you should initialize them (which erases all files). Moreover, you must initialize any partitions that you created in the disk partitioning step. About the only reason to mount a partition without initializing it at this point would be to mount a partition upon which you have already performed some part of the installation process using this same set of installation floppies.
Select the ``Next'' menu item to initialize and mount the / disk partition. The first partition that you mount or initialize will be the one mounted as / (pronounced ``root''). You will be offered the choice to scan the disk partition for bad blocks, as you were when you initialized the swap partition. It never hurts to scan for bad blocks, but it could take 10 minutes or more to do so if you have a large disk.
Once you've mounted the / partition, the ``Next'' menu item will be ``Install Operating System Kernel and Modules'' unless you've already performed some of the installation steps. You can use the arrow keys to select the menu items to initialize or to mount disk partitions if you have any more partitions to set up. If you have created separate partitions for /var, /usr, or other filesystems, you should initialize or mount them now.
An alternative to the ``Initialize a Partition'' step is the ``Mount a Previously-Initialized Partition'' step. Use this if you are resuming an installation that was interrupted or if you want to mount partitions that have already been initialized.