problem: allow to add new values on the fly

The "allow to add new values on the fly" function created with PHPRunner 5.2 build 4637 on Add or Edit page works with firebox 3.6 but not with internet explorer 8 on Windows 7. With ie 8, the add new page appears but does not take what you type. The save button does not close the pop-up window. Any body has similar problems? Or is there a work-round? Thanks.