Task Report Error

Hi All,

What could be the reason for error - Column Name (EVAL:@reason=index)
also attached is the code which is written for the column.
Any help is appreciated.

Thanks,
Sharayu

= 
if(
  isnull(
    pv!cdtPartNumberDetails.slaEndDate
  ),
  if(
    isnull(
      pv!cdtPartNumberDetails.requestCreatedDate
    ),
    {},
    rule!CEG_getWorkingDaysBetweenTwoDates(
      index(pv!cdtPartNumberDetails,"requestCreatedDate",{}),
      now()
    )
  ),
  rule!CEG_getWorkingDaysBetweenTwoDates(
    index(pv!cdtPartNumberDetails,"requestCreatedDate",{}),
    index(pv!cdtPartNumberDetails,"slaEndDate",{})
  )
) 
& 
if(
  isnull(
    pv!cdtMCADReqDetails.slaEndDate
  ),
  if(
    isnull(
      pv!cdtMCADReqDetails.requestCreatedDate
    ),
    {},
    rule!CEG_getWorkingDaysBetweenTwoDates(
      index(pv!cdtMCADReqDetails,"requestCreatedDate",{}),
      now()
    )
  ),
  rule!CEG_getWorkingDaysBetweenTwoDates(
    index(pv!cdtMCADReqDetails,"requestCreatedDate",{}),
    index(pv!cdtMCADReqDetails,"slaEndDate",{})
  )
) 
& 
if(
  isnull(
    pv!cdtECADDetails.slaEndDate
  ),
  if(
    isnull(
      pv!cdtECADDetails.requestCreatedDate
    ),
    {},
    rule!CEG_getWorkingDaysBetweenTwoDates(
      index(pv!cdtECADDetails,"requestCreatedDate",{}),
      now()
    )
  ),
  rule!CEG_getWorkingDaysBetweenTwoDates(
    index(pv!cdtECADDetails,"requestCreatedDate",{}),
    inhdex(pv!cdtECADDetails,"slaEndDate",{})
  )
) & 
if(
  isnull(
    pv!cdtClassifictaionDetails.slaEndDate
  ),
  if(
    isnull(
      pv!cdtClassifictaionDetails.requestCreatedDate
    ),
    {},
    rule!CEG_getWorkingDaysBetweenTwoDates(
      index(pv!cdtClassifictaionDetails,"requestCreatedDate",{}),
      now()
    )
  ),
  rule!CEG_getWorkingDaysBetweenTwoDates(
    index(pv!cdtClassifictaionDetails,"requestCreatedDate",{}),
    index(pv!cdtClassifictaionDetails,"slaEndDate",{})
  )
)