Xander - As Kevin mentioned, it would be good to know your operating system and any reproducible steps. By chance, are you using Windows XP? We are currently investigating an ArcMap crash that sometimes occurs when you open the help from a geoprocessing tool and then click links in the topic. So far, it seems to be only on Windows XP. If this is the same problem, we are working on a fix and will install it before the final release. Also, be sure to submit automatically any dump files that get generated (for this and any other crash you get!).
Thanks, Dan. We are considering doing this for the future.