Human error rather than software bugs caused multimillion-dollar staff overpayments by the State Rail Authority of NSW.
Data extraction and file handling errors contributed heavily to $5.6 million in overpayments made by State Rail since last February.
The excess payments occurred on four occasions of which two were related to "computer malfunctions" according to a Rail Authority press release.
However, chief financial officer Rob Noyes said the authority would be "hard pressed" to blame the problems on MIMS, its core enterprise package supplied by Mincom.
One incident occurred when "we had some back-pay to recalculate and the people who extracted the data did not do it properly," Noyes said.
A second incident involved double transmission of the same payroll file to the authority's banks.
On yet another occasion, a payroll run was based on data from a previous pay period containing large, non-recurring salary expenses.
Even through State Rail is not pointing the finger at the MIMS package it has been running for about two years, installing the software was not a happy experience for the authority.
In common with many large, integrated enterprise application projects, it created a number of headaches for the business.
"There were huge implementation issues we had to work through with Mincom on a daily basis," Noyes said.
Some of the difficulties stemmed from the software's deployment on a Unisys mainframe platform it was not designed for, he said.
Noyes described the situation as "more comfortable" since State Rail migrated to a Unix environment.