anchor.diff:              do j = 1,p%numBladeNodes
               
                  if ( VelocityIsZero( u%Vy(j,k)+m%TnInd_op(j,k)) .and. VelocityIsZero( u%Vx(j,k)+m%AxInd_op(j,k) ) ) then
  -                  call SetErrStat(ErrID_Fatal,"Blade"//trim(num2lstr(k))//', node '//trim(num2lstr(k))//&
  +                  call SetErrStat(ErrID_Fatal,"Blade"//trim(num2lstr(k))//', node '//trim(num2lstr(j))//&
                         ": residual is undefined because u%Vy + TnInd_op = u%Vx + AxInd_op = 0.",ErrStat,ErrMsg,RoutineName)
                     return
                  end if
  
positive.code:          do j = 1,p%numBladeNodes
              
              if ( EqualRealNos( u%Vy(j,k), 0.0_ReKi ) .and. EqualRealNos( u%Vx(j,k), 0.0_ReKi ) ) then
                 call SetErrStat(ErrID_Fatal,"Blade"//trim(num2lstr(k))//', node '//trim(num2lstr(k))//&
                      ": residual is undefined because u%Vy = u%Vx = 0.",ErrStat,ErrMsg,RoutineName)
                 return
              end if
  
negative.code:       do k = 1,p%numBlades            
           do j = 1,p%numBladeNodes
              if (.not. OtherState%ValidPhi(j,k)) then
                 call SetErrSTat(ErrID_Fatal,"Blade"//trim(num2lstr(k))//', node '//trim(num2lstr(j))//&
                        ": Current operating point does not contain a valid value of phi.",ErrStat,ErrMsg,RoutineName)
                 return
              end if
  