"The ICC has said that none of the umpiring mistakes were intentional and were part of the game. It has also said the UDRS system is working well and producing productive results," one source said.
The PCB had, on the request of its team management in South Africa after the first Test in Johannesburg, written to the ICC raising concerns over some of the decisions and the performance of umpire Steve Davis.
The PCB had also expressed reservations over the effectiveness of the hot spot technology used by umpires in the DRS system.
"The ICC has now sent its reply to the PCB and said that none of the umpiring errors were intentional and were just human errors," the source stated.
"The ICC also said the technology used in the DRS had helped reduce the number of umpiring mistakes and the correct umpiring decisions percentage had risen from 92 to 96 percent," he added.
He said in case of Davis, the ICC had reminded the PCB that it had a proper system in place to assess the performance of an umpire.
"The ICC has said that umpires whose performance was under review were given only one year contracts and if they didn't improve they were released from the panel," he said.
The PCB had asked the ICC to not post Davis in the remaining two Tests of the series that South Africa won by 3-0.