Kravis Center and top stagehand union leaders met throughout the day Thursday but were unable to resolve a 12-year contract dispute, forcing the cancellation of yet another performance of the Broadway hit, “Jersey Boys.”

The cancellation of tonight’s performance of the Tony award-winning musical biography of the 1960s pop group Frank Valli and the Four Seasons is the fourth this week. Since Tuesday, road crews for New York City-based Dodger Properties have refused to cross picket lines organized by local members of the International Alliance of Theatrical Stage Employees. With sets and wardrobes locked in nine semi-tractor-trailers, Kravis officials were forced to cancel Wednesday’s opening-night performance and two shows Thursday.

Late Thursday, neither side was available to answer questions about the status of the talks or the show, scheduled to run through Jan. 6, but the center stopped selling tickets Thursday. On its website, it said the action was temporary, blaming the strike.

Losses are clearly mounting. In 2010, Kravis officials said they grossed $4 million on the show, which packed the 2,195-seat main hall for the same number of days as are planned this year. It is estimated the center is losing about $100,000 in ticket sales each time a performance is canceled.

Members of the National Council of Actors’ Equity Association met in New York City and voted to support the local union’s “12-year struggle to achieve a fair and equitable contract with the Kravis Center.”

Besides a show of solidarity, the actors union said it wants the complicated sets to be built by union workers, citing their skill and experience and its concerns about safety. If the Kravis Center opted to use non-union workers, the association would inspect the sets to assure their safety before any actors would go on stage, said Maria Somma, a union spokeswoman.

This week’s blow-up is the culmination of a disagreement that began in 2000 when the center ended contract talks, fired six full-time union workers and threw the union out of the hall. The National Labor Relations Board, an administrative law judge and a federal appeals court all agreed the center engaged in unfair labor practices and ordered it to bargain in good faith.

Since the 2008 appeals court ruling, efforts to agree on a contract have failed. In August, the NLRB filed a second complaint, again alleging unfair labor practices. In the latest complaint, it claims the center in 2010 unlawfully declared an impasse in contract talks. It also said the Kravis illegally fired three employees and was using a core crew instead of filling stagehand jobs through the union-hiring hall as they are required to do.

Later, the NLRB said the Kravis owed stagehands at least $2.6 million in back wages. Union officials said they expect that number could double.

Kravis officials have denied wrongdoing, calling the allegations “alleged violations of labor law” and saying it will be up to an administrative law judge to determine their validity. They said union workers are paid a minimum of $24.77 an hour and pay can soar to more than $86 a hour under certain conditions.

Refunds are available by calling the Kravis Center box office at (561) 832-7469.