As your preview is missing the Create button etc it looks like you possibly may not have the required Table Permissions (i.e. Web Role your portal user is using does not have all the Table Permissions).
(when you are in Preview - did you login to the site, and if so do you then have the create button etc)
Out of the box the following Web Roles should have been created. Use the Power Pages Management App to check
Make sure your portal user (Contact) is using an appropriate one (e.g. anonymous would not by default have edit access but C1 Admin would) - by default the Anonymous and Authenticated roles are inherited unless you have turned it off or created /modified another role to inherit (note: you should not have multiple Web Roles set to inherit for Authenticated as the system will only apply one and you cannot be sure which one, and same for Anonymous)
Double check the Table Permissions Using the Power Pages Management App, you will find a set of Table Permissions that allow editing, creating etc double check that they have appropriate Web Roles linked to them (there is a subgrid of Web Roles on the form when you open it)