Los Angeles Superior Court Judge Richard E. Rico dismissed the case against David Joseph Klein, 50, according to documents filed Monday.
Duff and Madden had sought restraining orders against Klein and Maksim Myaskovskiy, 18. Myaskovskiy has been charged with stalking the singer-actress after police said he called a private security firm employed by Duff last month and threatened her and Madden.
Myaskovskiy has pleaded not guilty. He remained jailed Thursday, awaiting a court appearance.
Court papers had alleged Klein relayed messages from Myaskovskiy, his former roommate, to Duff.
The case against Klein was dismissed "based upon his apologies for any misunderstanding, his cooperation, and his assurances that he will not seek further contact with Ms. Duff, Mr. Madden, or any of their family members or representatives," according to a statement released by Duff's representatives at the Rogers and Cowan public relations firm.
A telephone listing for Klein could not be located, and it was not known whether he had a lawyer.
Duff is best known for starring in the long-running Disney Channel show "Lizzie McGuire."