I've discovered and been able to re-produce a bug in the 'pdfforge Toolbar v4.7' which is causing Internet Explorer 8 and 9 (Windows XP and Windows 7) to crash. As everyone here seems to be aware, this component is installed by default with PDFCreator.
The problem is re-producable with multiple different versions of PDFCreator (I didn't bother to check the toolbar versions) including the latest release. The crash occurs under fairly limited circumstances but is clearly a problem with the 'pdfforge Toolbar'.
I've sent sample code to Spigot for their review.
Our clients have been using the PDFCreator for several years and this is apparently the first experience of a crash. Their problems were reported on the 19th October so would appear to co-incide with the PC's being updated to the latest release of PDFCreator.
The toolbar appears to serve no purpose hence we've advised them to disable it.