If I were you I would put the ‘mainform’ to one side and create yourself a simple test form to work with so you can prove the concept and see what it does..
set up your form connection ACTION to READ from your DBform where you set up the RETURN parameters to the column in your table that stores the names. You don’t specifically need any ‘send parameters’. you will then be shown TEST.. try it to see what it returns (ie it should return the content of that table from your form instance on the DBForm table)
then on your ‘test’ form, add in a drop down and a button. under the button set up your ‘connect’ action to this form action and then preview the form, hit the button and you should see the drop down populating.
in terms of populating a drop down from a connection, note that in the Return Parameters section of the Connect script , check the Items option corresponding to the field you want to populate you list or drop-down object with