I already responded to you about this issue via our support system, however, in case anyone else is experiencing this problem, I'll copy my response below:
> I just tested this on a local machine and on bitbucket.org with a
> private mercurial repo (with a private issue tracker) and a public
> mercurial repo (with a public issue tracker).
> I was able to get a simple test of a commit with the message including
> "(closes #1)" to close issue #1.
> Are you sure the Issue service is enabled for the repos you are having
> problems with?
Edit: The code block formatting of my email's contents is incorrectly changing what should read "(closes #1)" to "(closes <left-angle-bracket><left-angle-bracket>issue 1<right-angle-bracket><right-angle-bracket>)".
Issues tracker doesn't seem to work for me. I have a private repo with Issues enabled, i created an issue using the web interface and made a lil change locally + commit + push with a "fixes #1" message.