anchor.diff:        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(k))//&
  +               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
  
positive.code:             do j = 1,p%numBladeNodes
              
                 if ( EqualRealNos(z%phi(j,k), 0.0_ReKi) ) then
                    call SetErrStat(ErrID_Fatal,"Blade"//trim(num2lstr(k))//', node '//trim(num2lstr(k))//&
                         ": residual is discontinuous or undefined because z%phi = 0.",ErrStat,ErrMsg,RoutineName)
                    return
                 else if ( VelocityIsZero(u%Vy(j,k)) ) then
                    call SetErrStat(ErrID_Fatal,"Blade"//trim(num2lstr(k))//', node '//trim(num2lstr(k))//&
                         ": residual is discontinuous or undefined because u%Vy = 0.",ErrStat,ErrMsg,RoutineName)
                    return
                 else if ( VelocityIsZero(u%Vx(j,k)) ) then
                    call SetErrStat(ErrID_Fatal,"Blade"//trim(num2lstr(k))//', node '//trim(num2lstr(k))//&
                         ": residual is discontinuous or undefined because u%Vx = 0.",ErrStat,ErrMsg,RoutineName)
                    return
                 end if
  
negative.code:             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(j))//&
                        ": residual is undefined because u%Vy + TnInd_op = u%Vx + AxInd_op = 0.",ErrStat,ErrMsg,RoutineName)
                    return
                 end if
  