Army National Guard units have seen their paychecks repeatedly botched by a payroll system that is not equipped to process active duty personnel, the General Accounting Office (search) reported in a study released Thursday.

"Delays in submitting documents, incorrect data entry and limited personnel to process the mass mobilizations" all contributed to the problems soldiers experienced in getting paid, the study said.

The GAO studied six National Guard units across the country and extrapolated from those units a pay system "so cumbersome and complex that ... mobilized Army Guard soldiers cannot be reasonably assured of timely and accurate payroll payments."

The GAO study found that 94 percent of soldiers in the six Guard units surveyed "encountered problems with earnings calculations during one or more steps of their mobilization, deployment or demobilization," Rep. Christopher Shays, R-Conn., said Thursday. Shays is vice chairman of the Committee on Government Reform, which asked for the study.

Of the 90 soldiers in the Salisbury, Md.-based 200th Military Police Company (search) initially mobilized in October 2001 to guard the Pentagon, 83 of them experienced "at least one pay problem," the report revealed.

One soldier did not start getting correct payments until seven months into his mobilization. Soldiers in the company were overpaid by about $74,000, said the GAO, which also discovered $11,000 in underpayments and $10,000 in late payments.

"We didn't realize prior to this how pervasive a problem it was," said Rep. Wayne Gilchrest, R-Md., who represents the area where the guard unit is stationed and has visited with company soldiers at home, in Cuba and in Baghdad. "When they put their life on the line and when they're away from their families for so long, people really need to get the paperwork done right."

The Defense Joint Military Pay System-Reserve Component (search) — the system used to process payrolls for guardsmen and reservists — is plagued by problems, the report said. According to GAO, the system was "originally designed to process payroll payments to Army Reserve and Army Guard personnel on weekend drills, on short periods of annual active duty ... and for training."

But that system, which depends on manual data entry and re-entry, is being stretched to the limit now as is it used to pay guardsmen on active duty.

"As a result, it was often difficult to ensure that mobilized soldiers received only and all the pays and allowances to which they were entitled," the GAO study said.

"While not designed as such, these pay operations have evolved over time to the point that few, if any, in the department fully understand their breadth, scope and inherent weaknesses," the study said.

The GAO recommended that the Defense Department take several steps aimed at streamlining the way guardsmen are paid, including clarifying payroll policies and procedures, and updating and integrating the payroll system.

The 200th Military Police Company, which responded to the Pentagon on Sept. 12, 2001, and stayed there for two weeks after the terrorist attacks, were called up for active duty on Oct. 1, 2001.

Following three weeks of training, most of the unit was sent back to guard the Pentagon, while three soldiers were sent to Guantanamo Bay, Cuba.

The unit was demobilized in August 2002, but some of the soldiers were later transferred to another unit that was deployed to Baghdad.

GAO has followed the pay schedule for them since their call-up. Gilchrist said he plans to contact those guardsmen still on active duty to see if the situation has improved.

"Over the next couple of days, we'll make some inquires to make sure none of those folks are having any problems," he said.