Permissions for full functionality

I'm having difficulty actually using the e-newsletter plugin.

First, I had to chmod the uplaods directory before I could get it to upload anything.

What I'm wondering now is what the general security/permissions should be for everything else.

Every features works fine for me except the 'Preview' pane and the 'Actions' submit buttons.

Clicking on preview does nothing, and clicking on save newsletter or save newsletter and go on to send page does nothing.