Hi Josie,
First idea is that you are not actually publishin the form, or when you do publish you aren't opening from the published location. This could be caused by a caching bug. To clear your cache, click Start and InfoPath and remove the form templates that you were using for your form template. Then, open again from the published location and InfoPath locally will download and cache the new form. Maybe that fixes your problem.
The second idea has to do with domains... When you publish the form are you publishing it to the same site where the SharePoint list lives? If not, is the location where you are publishing to in the same Intranet domain as the SharePoint list?