Version:            (using KDE KDE 3.5.6)
Installed from:    Ubuntu Packages
OS:                Linux

As reported and confirmed in Ubuntu: https://launchpad.net/ubuntu/+source/kdebase/+bug/91509

Konquerer crashes if one gets a popup window which has a link to some content that creates the "open with" dialog, closes the popup window (before choosing one of the "open with" options), and only then chooses one action. My guess is that there is a code reference (a pointer) to the parent window ( to make some kind of back-notify, maybe to return focus? ) which segfaults because there is no parent window anymore.
Example ( not that this is not particular of this URL, this is reproductible with any kind of page/site where we can follow this sequence )
1 - open web page from wich you can have a popup window (http://209.161.33.50/dictionary/crash)
2 - open the popup (in this example, click the red speaker image after "Main Entry: crash"
3 - the popup window has a wav file, which triggers the appearance of "Open '...' ?". Do not choose an option here and instead, close the popup window.
4 - choose one option from the "Open '...'?" window. Konqueror will crash.