The inhabitants of Errikang VII were previously acquainted with Q; Vash was nearly killed visiting the planet while in Q's company. (DS9: "Q-Less")
According to Startrek.com, the pronunciation for Errikang VII was "AIR-ih-kang". 
According to the Star Trek: Star Charts (pg. 75), the Errikang system was located in non-aligned space in the Gamma Quadrant. This was a single star system. Primary was a Class A star with a magnitude of +5, which was the same brightness as Sol.