The proper way to report bugs in Webwork problems is this:
1. While you are logged in to Webwork and you're looking at the problem which has the bug, click "Edit this problem"
2. On the page that pops up, click "report problem bugs."
3. The Bugzilla page pops up. I think the first time you're here, you need to create an account. Later on, you seem to be logged in automatically.
4. Fill out the form.
This way your report is automatically directed to the person who can correct the error.