kill -KILL fails to kill process

[Steve Franks]

Which I thought was impossible.  Neophyte question, no doubt, but
googling was less than helpful (which probably means I'm fubar, no
doubt).  Anyway, I have a certain common X app (xmms) that likes to
hang (since my last buildworld, it seems) when when it's right about
to open a file-choosing dialog.  The only way to get rid of it is to
reboot.  Now, given the behavior, I'd have to suspect something
underlying as the true source of the problem, but shouldn't kill kill
it anyway - I mean, isn't there some way to kill a process that's
stuck waiting on a child process?  I haven't figured out how to "ps
-ax grep | some neublous file dialog process" yet...so I'm sort of
stuck wanting to kill the parent...

Thanks,
Steve