SEOUL, JULY 26 -- A last-minute dispute over logistics led to the abrupt cancellation today of a meeting planned here between North and South Koreans, highlighting the fragility of efforts to end decades of mistrust and hostility.

For the first time in five years, a delegation of North Koreans was to visit Seoul for a meeting with South Korean dissidents. The North Koreans -- five government officials and 10 reporters -- went to the border crossing at Panmunjom but refused to enter South Korea after a dispute with the South Korean government over which hotel they would stay at and whose cars they would travel in.

The day had begun more optimistically with the signing of an accord to hold meetings in September and October between the two Korean prime ministers in what is to be the highest-level contact between the countries since the 1950-53 Korean War ended in a truce. The two Koreas have never signed a peace treaty.

But today's dispute illustrated the difficulties that crop up when the Koreas try to discuss even the simplest of matters. While today's disagreement was over hotel rooms and autos, the prime ministers will have to come to grips with issues such as troop cutbacks and nuclear weapons -- if their meeting actually takes place.

"Things have been canceled before, and they could be canceled again," a diplomat said.

Over the past few weeks, the two Koreas have been caught up in a frenzy of proposals and counter-proposals for various exchanges to mark the 45th anniversary on Aug. 15 of Korea's independence from Japanese colonial rule. The most dramatic suggestion came last Friday from South Korean President Roh Tae Woo, who called for a five-day trial opening of the border. North Korea brushed the idea aside as a trick.

Today's attempted border crossing stemmed from a North Korean plan to hold a unification rally at Panmunjom on Aug. 15. North Korea invited South Korean dissidents to attend the rally, and South Korea's government surprisingly gave a green light this week to a meeting in Seoul to prepare for it. North Koreans last visited Seoul in 1985 for an exchange of divided families.

Seoul officials have made no secret of their dislike for the rally, which they say could take on an anti-South Korean tone and deflect attention from their call for broad cross-border exchanges. But they say they will support the rally if South Koreans from all walks of life -- not just dissidents -- can take part.

According to South Korean officials, the North Koreans agreed this morning to travel to Seoul in cars furnished by the South Korean government and stay at the Intercontinental Hotel. They later demanded, along with the South Korean dissidents, to travel in vehicles furnished by the dissidents and stay at a hotel chosen by them.

Hours passed as liaison officers from both sides haggled. South Korea argued that it would be difficult to ensure the safety of the North Koreans if they traveled in the dissidents' vehicles and stayed at the site chosen by them in northern Seoul.

By the end of the day, North Korea reportedly had broken off the discussions. Later, each side released statements accusing the other of looking for excuses to abort the meeting in Seoul. South Korean dissidents waiting for the North Koreans at Panmunjom shouted anti-government slogans, such as, "Down with Roh Tae Woo, who blocks unification!"