Donors pledged about $17 million for expenses in 2010, money far short of the $85 million that they need for 2010 and 2011.
A judge says an investigation into further cases cannot take place until the court deals with its second trial.
The Cambodian side of the hybrid court is facing dire economic circumstances, with staff salaries halved in April.
The Khmer Rouge tribunal verdict for Kaing Kek Iev, the torture chief better known as Duch, will be announced July 26.
In Cambodia, May 20 is known as the Day of Anger.
The delegation of four will assist in a pledge meeting on May 25 to solicit promises of funding from donor countries.
This memorial was one of more than a hundred that have been going up around villages in Cambodia.
The CPP held a ceremony “for national reconciliation” and “to remember our pain” under the regime.
“Breaking the Silence” urges victims and perpetrators to address their collective trauma.
The tribunal allows “civil parties,” or victims of the regime, a measure of participation in trials.
An estimated 500,000 Cambodian Muslims died under the Khmer Rouge, through overwork, starvation or execution.