Most likely out of country voting was abandoned in 2004. See Article 5.5 of the Electoral Law.
THE ELECTIONS LAW (last amended on December 15, 2014)
Article 5.2. Where To Vote
A Liberian citizen who has attained the age of 18 years or above with a valid Registration card shall vote only in the voting precinct of the electoral district for which he/she is registered.
Article 5.5. Absentee Voting [Omitted in 2004]46 (see below)
46 Section 5.5 “A registered voter who is absent from the country during an election and wishes to vote shall request the Commission [by] registered mail for an absentee ballot forty-five (45) days before an election. Absentia votes shall be directed directly to the Commission by registered mail for inclusion into the result of the elections.” was deleted by An Act Suspending Certain Provisions of the Constitution of Liberia and Amending Specific Sections of the New Elections Law 1986 and Approving New Provisions Relating to the Budget Appropriations of the National Elections Commission, approved December 17, 2004 and published December 23, 2004, section 18.