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Due to the increasing importance of concurrent programming and distributed computing systems, possessing a good understanding of concurrency and its impact on process synchronization is essential. Since concurrency introduces design and execution issues not found in sequential programming, to learn about concurrency issues, it is important that students gain hands on experience actually doing concurrent programming. The best way to get this experience is by using a system developed specifically for teaching concurrent programming. The Ben-Ari Concurrent Interpreter (BACI) is such a system. Unfortunately, when errors are encountered in BACI programs, they are cumbersome to debug. The purpose of this paper is to introduce and describe a Java-based graphical user interface debugger for the BACI language.