Please make sure that you've read the documentation before submitting a bug report. If you're sure you've found a bug - e.g. if one of my programs crashes with an obscur error message, or if the resulting file is missing part of the original data, then by all means submit a bug report.
I use GitHub's issues system as my bug database. You can submit your bug reports there. Please try to be as verbose as possible and answer at least the following questions:
If at all possible please provide sample files as well so that I can reproduce the issue. If you don't have a place to upload them to, you can upload them to my SFTP server.