Bugs are a constant problem with software development. In HtmlUnit, there are several factors for the cause of bugs. These include: bugs in third-party code, functionality that still is not supported by HtmlUnit, bugs in your code, or true bugs in HtmlUnit. To track these bugs, we are using the SourceForge issue tracking system located at http://sourceforge.net/tracker/?group_id=47038&atid=448266
Before reporting an error, make sure that you are up to the latest version of the software. If you can, get the latest snapshot, or build it from Subversion to see if the error still occurs. Check the dependencies to be sure that you have all the required jar files. Also, review the list of bugs and recently closed bugs to see if someone else has already reported the bug. If they have, you may want to just add more detail to it.
Development of HtmlUnit is done as a volunteer effort. As such, the developers respond when they get a chance. There are a number of things that you can do to help get a quicker response