9e7742db_ime_manipulation___Heroes_Wiki__Theory
[Citations] When Hiro seems on the verge of saving Charlie and thus causing a causality paradox, he returns unexpectedly to the present. (Six Months Ago) In the novel Saving Charlie, Hiro makes several attempts over a six month period (though much longer for him) to try and put Charlie out of harm's way. These attempts, along with his first few attempts at intimacy with Charlie, result in Hiro teleporting someplace else relevant to his "destined" mission (i.e. saving Claire), such as the morgue where James Walker's body is being stored. [Notes] + Hiro's forced return to present-day Japan and inability to use his powers to go back and make further attempts to save Charlie Andrews suggest that something is blocking his ability to go back to that specific point in space. + Also, Future Hiro has to get someone else to go back to present-day Odessa to save Claire rather than taking matters into his own hands, perhaps due to his inability to return to that point in space and time due to a rift his past self created. - If this were true, then Hiro shouldn't have been able to change the events of the explosion, because Future Hiro wouldn't have come back and told Peter to save the cheerleader. • If this is true, then it could be the same cosmic authority that controls Hiro's "accidental" time travel, in Genesis, Five Years Gone, and How to Stop an Exploding Man. Perhaps the authority is not simply keeping Hiro from causing paradoxes, but actually making sure he goes where he needs to go. • This "cosmic authority" could be the writers. - Hiro eventually did save Charlie's life (Once Upon a Time in Texas). • This once again hints that the "cosmic authority" are indeed the writers. [Theory] 
There is some kind of higher-power/cosmic authority that prevents Hiro from creating paradoxes.
Theory:Space-time manipulation - Heroes Wiki
Theory