Having same problem with inability to change registration field input widths, both text and textarea seem to be fixed. Couldn't find solution posted in this topic.
Just installed a fresh Joomla 1.6.3 and CB 1.4. Text boxes seem to be about 25px, no matter what I set the fields to, textarea is the same width, but expandable in FF5, static in IE9. Tried playing with both field configuration in CB and CSS for CB & template. Can't seem to change it. Checked MySQL and the field sizes are recorded properly in the database, so it seems like it would have to be CSS issue. But there isn't anything in my site template for textareas, so I'm back to looking at CB CSS.
Attached the screenshot from IE. The text fields are supposed to be 45px and the textarea should be 500px (100% width).
Anyone have any ideas? Thanks!