A national activist group is planning to launch a media blitz against Fidelity Investments and Berkshire Hathaway for their investments in companies doing business with Sudan - which critics say is committing genocide against its own citizens in Darfur. The Save Darfur Coalition said it will unveil details today of what is expected to be a national and local television ad campaign criticizing both Fidelity and Berkshire Hathaway [sic]. Actress Mia Farrow, who was recently in Boston pushing for a new state law cutting all government investment ties with Sudan, is expected to attend a press conference outlining the upcoming media blitz. The Save Darfur Coalition’s plan is just the latest action against Boston-based Fidelity, which has been the target of protests by other groups over its investments in PetroChina, which does business with Sudan. A Fidelity spokeswoman yesterday reiterated that the firm is complying with all U.S. laws in regard to Sudan - and will go along with tougher sanctions if so ordered by the feds. Separately, a University of Massachusetts committee directed managers to divest more than $530,000 of its investment funds from any companies doing direct business with Sudan. UMass is the latest college to divest its funds from firms with direct ties to the African country.