Bugs Online
Computers, Software, Configuration Management, Bug Tracking - Bugs Online. A free (GPL) bug tracking system for use with Microsoft IIS, Access and ASP.
https://bugsonline.sourceforge.net/
Roundup Issue Tracker Roundup v1.4 documentation
Computers, Software, Configuration Management, Bug Tracking - Roundup. A simple-to-use and -install issue-tracking system with command-line, web and e-mail interfaces.
https://roundup.sourceforge.net/
Teamatic
Computers, Software, Configuration Management, Bug Tracking - Teamatic. Free web-based bug tracking, ticketing and project resource tracking system.
http://www.teamatic.com/
Mantis Bug Tracker
MantisBT is a popular free web-based bug tracking system. It is written in PHP works with MySQL, MS SQL, and PostgreSQL databases. MantisBT has been installed on Windows, Linux, Mac OS, OS/2, and others. It is released under the terms of the GNU General Public License (GPL).
https://mantisbt.sourceforge.net/
Project Management Software
Computers, Software, Configuration Management, Bug Tracking - elementool. A free bug tracking and managing tool, on the Web, supported by advertisements.
http://www.elementool.com