nth-child problem with generated table

nth-child problem with generated table

I'm creating the header and first line of a table and use jQuery to duplicate the first line. I'm then having trouble accessing a particular columns input field. I've created a small demonstration and it seems to work in Firefox 3.6 and IE8 but doesn't work in Safari 5 or Chrome 9. It should put an 'A' in the field 3 input box.

Any work arounds?