ActiveX is a proprietary Microsoft standard that allows them and others to develop 'mini-programs' that can be called and run by a wide range of programs (in this case, a web browser).
The 'unstable' part usually relates to the code (that runs an error-checking routine on ActiveX components) reporting that the ActiveX code is trying to use memory that it shouldn't be.
Without knowing the ActiveX control it is not possible to say for sure what the problem is.
The two most likely causes are a badly-written ActiveX component that that particular Web page has decided to use, or a 'damaged' ActiveX component that is used by Internet Explorer.
For now, click anywhere on the page, press Ctrl-A and then Ctrl-C (to highlight everything on the page and then copy it). Then open a program such As Word, press Ctrl-V to paste the web page into Word, and print from there.
Is this happening with all web pages, or just a specific sites?