This may or may not be a bug, but I wanted to report it just in case.
I'm running Wireshark 0.99.5-5.3 here on OpenSUSE 10.2, installed from the RPM that's on rpmfind.net. If it matters, I'm using Gnome.
I can run Wireshark ok, and it seems to work great. I'm a normal user, so on startup it I'm prompted for root's password. That goes fine, and it starts and I can capture packets no problem.
The problem happens when I try to use File/Save or File/SaveAs to save the packets to a file. Wireshark hangs, and has to be killed. I see the same thing happen with File/Open to open a previously saved file.
On http://www.wireshark.org/faq.html it says to try to get a core dump. I tried kill-6 to get a coredump, but while it did get Wireshark to die, it didn't produce a coredump.
This is 100% reproducable here, so if there's something I can try or test that would help, please let me know. Since this would be such an obvious problem, I'm hesitant to call it a bug.
I see that there's a 0.99.6 release, but I haven't yet got the right bits and pieces in place to build it from source on this machine.