The $852 bill for Frank Shaffer-Corona's trip to Cuba, which the D.C. school board member, thought was safely on its way to being paid by the city government, has run into a serious roadblock in the D.C. finance office.

Charles E. Davis, a career government employe who is the city's chief accounting officer, has decided not to approve a check reimbursing Shaffer-Corona because it would be a "questionable payment."

Instead, Davis said, he has asked the U.S. comptroller general for a ruling on the legality of using government funds for the trip.

Shaffer-Corona, 35, made the two-week trip to Havana in late July and early August, despite protests by school board president Conrad Smith, to attend the 11th World Youth Festival of Youth and Students.

He described the festival, which was attended by about 20,000 young leftists from 140 countries, as "an educational conference," for which he could use school board funds.

But Davis said in an interview: "It was a very unusual (government) travel authorization, and I want the comptroller general's opinion before we pay it."

Even though the District has home rule, said Davis, it still receives all its funds through congressional appropriations and thus is subject to rulings by the comptroller general, Elmer Staats, like all federal agencies.

In a letter to Staats, who oversees the General Accounting Office, Davis said Shaffer-Corona's travel vouchers showed no indication "of the benefit to be derived by the (District) government . . . from the trip."

He also sent copies to Staats of material on the youth festival that Sfaffer-Corona had given to the school board. The material includes the text of a statement Shaffer-Corona made to a Havana "tribunal" called "Youth Accuses Imperialism," identifying himself as "the representative of La Raza Unida Party to this festival."

The party, a small Mexican-American group, is based in Texas. Shaffer-Corona serves as its Washington representative.

"I went down there (to Havana) wearing two hats," Shaffer-Corona said in an interview, "as the representative of La Raza Unida and of the D. C. Board of Education . . . The workshops and seminars that I went to dealt with education . . . Davis doesn't run my office and I don't run his. It's not in his purview at all (to block the travel funds.)"

Shaffer-Corona said the Raza Unida party paid nothing for his trip.

In his statement in Havana, Shaffer-Corona condemned the United States as "the most successful police state in all of history," and declared that at the end of World War II "the headquarters of National Socialism was moved from Berlin to Washington." He described Washington as "the capital of the monster."

The United States is "owned" Shaffer-Corona said, by "monstrous fiends . . . such as the Rockefellers, Mellons and Kennedys' who are "killing their own people with fiendish subtleties . . . (for example) cancer in the water supply, chemicals in the food, cancer in the tobacca, cancer for two generations in the birth control pills . . ."

Shortly before Shaffer-Corona left for Cuba, board president Smith tried to block his request for a $756 advance. A board majority overruled Smith, but there was not enough time to complete the paperwork before Shaffer-Corona left town, and the advance was never paid.

Shaffer-Corona submitted his vouchers for repayment on Sept. 19 and Oct. 4.

According to U.S. organizers for the festival, a package trip, including air fare, fees, food and lodging, cost $500. Shaffer-Corona said he spent an additional $352, mostly for food and hotel accomodations in downtown Havana.

"Let's call it a cost over-run," he said, "similar to the overruns incurred by the Pentagon, which are always repaid."