This information is available from EPK on the sidebar of their homepage:
Note: As stated below this is a Microsoft issue and we have no word at this time when it will be fixed.
To all EPK-Suite Customers:
We have identified a problem running EPK-Suite with the production release of Internet Explorer 7. EPK has reported this problem to Microsoft and they have confirmed there is an issue which causes modal dialogs and message boxes to disappear on their own, and that modal dialogs are not behaving as “modal”.
This is an extremely serious problem and one which other development firms have also identified. EPK had tested EPK-Suite with the beta versions of IE7 and this problem did not exist at that time. It was introduced very late in the IE build cycle and is in the production release of IE7, available now.
Microsoft has their teams working on this issue and a “fix is in the works” according to postings on MSDN. Obviously any fix cannot be in the production system which just shipped and is scheduled for automatic download to customers soon.
We have no timeframe from Microsoft on when this fix will be available, but they are working on it.
Until we have received the fix and fully tested it, do not run EPK-Suite with IE7. You should block the scheduled automatic download of IE7 to machines running EPK-Suite.