DMX?is on the hook for another $630,000 — this according to a booking agency which claims X’s legal problems torpedoed a lucrative international comeback tour … and now, it’s suing to get its money back.

The booking agency in question — a company called?Heavy Rotation?– filed the lawsuit in New York, claiming it struck an exclusive year-long deal with DMX in 2011 to book the rapper’s concerts … anywhere on the planet.

But according to the lawsuit, DMX was plagued with legal problems from the start –?a traffic violation in August, and two nasty child support disputes … which led to a lien on the rapper’s passport, preventing him from performing overseas.

According to the suit, HR bent over backwards to fix the legal issues — coughing up nearly a hundred grand to cover bail, child support, and a slew of other legal bills … hoping it would clear the way for the tour, a task that included lifting the lien on X’s passport.

But HR claims its efforts were in vain — because DMX continued to cause problems, hiring outside management that tried to book DMX on shows within the United States … violating X’s agreement with HR. On top of that, X couldn’t resolve his passport issues … and all concerts had to be canceled.

X’s manager Jason tells a different story — claiming DMX chose to sever all ties with HR after it put the rapper at risk with some unsavory business practices.

Still, HR claims it lost $749,285 on the deal gone bad — and it wants the money back, stat.