Software architecture has received increasing attention of practitioners and researchers, since it has played a significant role in determining the success and quality of software systems. At the same time, the success of Open Source Software (OSS) has also sparked interest of researchers in the universities and in the software industry. OSS has been largely used and developed and, as a consequence, the OSS quality has been a concern and an interesting subject for researchers. However, in spite of narrow relation between software architecture and software quality, there is lack of more detailed works that investigate how software architecture can influence OSS quality. In this paper, we present a case study reporting how software architecture is directly related to OSS quality. We have hence proposed architecture refactoring activity in order to repair software architectures, aiming at improving mainly maintainability, functionality and usability of these systems.