Can't Close Dialog Box After Emailing Quarantined Files

After installing the latest Home version update (4.8.1229) and running a weekly scan using VPS 080725-1, I got what I believe to be a number of false positives. These were sent to the chest so that they could be emailed to Alwil from within the application. There were no problems sending the email, but after the successful transmission I was returned to the dialog where additional information can be added to the submission. I could not close this dialog using either the Cancel button or the close window button. The only way out of this infinite loop was to kill the process using the Windows Task Manager.

The system is a Compaq Presario laptop running Windows XP Home SP3, fully patched.