I followed the instructions on how to setup qimportbz here; I'm on WinXP and instead of adding:
[extensions]
qimportbz = C:\mozilla\mercurial\qimportbz
to a .hgrc file I updated a Mercurial.ini file which seems to be the correct file to add extensions to for me..
then when I run hg help qimportbz I see the help for the qimportbz cmd, but when I try to run hg qimportbz 548590 for example, on the jetpack-sdk hg repo, I get the following error:
hg: unknown command 'qimportbz'
Try instead to declare the extension in your <repo>/.hg/hgrc file, just to check if that has any influence on the issue.
What does your hg debugconfig show? Any mention of qmimportbz? There's a chance you need double backslashes each time you use them, but the output of debugconfig should make that clear if it's the case.
FWIW either .hgrc or Mercurial.ini will work for you. On unix-alikes only .hgrc is checked, but on Windows both are. See the hgrc man page for details on that.
I had this problem. I believe the syntax has changed. Try hg qimport bz://bug_num where *bug_num* is the bugzilla bug id.