polkit-gnome-authentication-agent-1 crashed with SIGSEGV when uusing Synaptic Package Manager to install additional software seems simioar to #649860

If you're sure your issue is the same as bug 649860, you can go to that page and indicate that the bug affects you (by using the green link near the top of the page). You can also subscribe to that bug. If you have any additional information to provide about the bug based on your experience, you can post in the bug with that information. In particular, if you're using an architecture (examples of architectures include: i386, amd64) or an Ubuntu release (examples of Ubuntu releases include: hardy, lucid, maverick, natty) which the bug has not yet been documented to affect, you should mention that you have reproduced the bug with that architecture or release, and if the bug occurs on your system in a way that is different from the way that it has already been reported to occur, you should make sure to post and provide that information.

However, if you think that it is at all plausible that you may have a different bug, then you should first study that bug report in detail (if you have not done so already). Perhaps you will figure out if your bug is the same, by doing that. If you have specific issues you wish to ask about, regarding whether or not your bug is the same, then you could ask those here in this question.

If after examining that bug report you believe that your bug is not, or might not be, the same as the bug in that report, then you should file a bug report. To do this, first read https://help.ubuntu.com/community/ReportingBugs carefully. That document explains how to report a bug. Since this bug is a crash, you should report it with Apport (configured to launch when the crash occurs). If you need help with that, please feel free to ask here, in this question, but please read https://help.ubuntu.com/community/ReportingBugs first. That page also explains how to search for other bugs that might be the same as yours (though it sounds as if you *might* already have done that).

If you report this as a new bug, you may want to mention bug 649860 in your description. If you say "bug 649860" or "bug #649860" then that text will be automatically made into a link (which is good, it makes it easy for people to click the link and see the related bug report, and encourages them to do so). Whereas, if you just say "#649860", that will not be made into a link. If you think it's possible that the bug you're reporting is a duplicate of bug 649860 after all, then you should *definitely* mention bug 649860 and say that you think the bug you're reporting might be a duplicate of that bug.

If you report this as a new bug, you can use the "Link existing bug" link on this question page (https://answers.launchpad.net/ubuntu/+source/synaptic/+question/150069) to link the bug and this question to each other. That's the link I used to link this question with bug 649860. It's a good idea to do that, but your bug report should be complete and self-contained; it should not be necessary for the Ubuntu developers to refer to this question in order to fully understand, appreciate, and evaluate your bug report (including evaluating its status as a possible duplicate of bug 649860).