the progress bar code needs to be removed manually, there is not an automated process for removing the progress bar.
for the problem you are having, fixing the progress bar is the best solution. Most likely the problem is that the script files for the progress bar are not uploaded to the server, make sure to upload the webassist/progress_bar folder.
any redirect used in the UE will only happen after the emails have been sent.
as far as leaving the page in the middle of sending the emails, this is not something that can be done in the php code, it is something the site visitor would do, either closing the browser, or going to another page.
