Hi Erin, from Dallas, welcome to the Moodle community. You can get all sorts of information about Moodle, all sorts of help, but there are a couple of things you need to know. One is that for help on installation errors, go to the Installation forum, for help on the database activity, go to the database forum, for help on the choice activity, go to the choice forum. Most plugins, activities and resources have their own forums, so you really got to pick the right one sometimes. If you are not sure, just go to the General Help forum, which is probably the best place to start, and put your questions there.
The second thing, and this is really important, you need to define the error or problem, clearly, and if you are getting an actual error message, include that as well. Give as much information as you can about the error or problem. The more information the better the opportunity the community gets to finding the right solution quickly.
Having said that, let's take a stab in the dark.
I am assuming this is an error you are getting while still installing. The Database is telling you that it is not being created or you do not have access or similar.
There are several possibilities, main one being Ubuntu has not properly installed the database. For most Moodles, the default has been MySQL, so you have to make sure you have MySQL installed and properly configured. With V2.x, I am sure, you do not have to create the database first, Moodle should do that for you. However, you need to make sure that the database is properly named, eg Moodle281 for the version you are installing. Second you need to make sure the root password you have given when installing MySQL is the same password you are giving the Moodle installer. Without the right password, it can't access MySQL or create the database.
These are the most common ones, for this stage of installation. There are others, but if you have gotten past this point, then there is something else going on. Without any information though, it is hard to help.