The Cambodia scenes had to be cut out from the original version due to recent clashes between Cambodia and Thailand over the Preah Vihear temple.
The production of the film was notoriously troubled. Star Tony Jaa insisted on making his directorial debut with the film, which soured his relationship with Prachya Pinkaew, the director of his hit films Ong-bak (2003) and L'honneur du dragon (2005). Once filming was underway, stories began circulating about Jaa's strange behavior on set, such as sacrificing chickens every day before shooting and the film very quickly went behind schedule and over budget, until one day Jaa didn't come to set and remained missing for around two months. Rumors surrounding his absence revolved around his inability to handle the pressure of making the film leading him to hide out in Cambodia and practice black magic. Jaa's mentor, martial arts choreographer and director Panna Rittikrai eventually tracked him down and brought him back, after which Jaa appeared weeping on television, promising to finish the film. Right after this however, he threatened to disappear again unless production company Sahamongkol agreed to a set of demands, including releasing him from a ten year exclusive contract with them. Jaa was then seeing being forcibly taken into a car, leading to speculation the production company had kidnapped him. Jaa reappeared hiding out in a police station where he met with Sahamongkol boss Sia Jiang, dropped his demands and agreed to have Rittikrai come on as director, Luc Besson to be made and a new character being created for actor Dan Chupong.