For the following AMPL $(.$mod, $.$dat, $.$run,$)$ I receive the error messages copied at the end. Modify the codes to get a model in a way such that for each AGV a Rack should be assigned and each Rack should be assigned to a workstation, respectively.

$.$mod;

# The sets

set Racks; # Set of racks

set AGVs; # Set of AGVs

set Workstations; # Set of workstations

set Axes$=\{"$x$","$y$"\}$;

# Parameters

param rack$\_$location$\{$Racks$,$ Axes$\}$ symbolic;

param rack$\_$status$\{$Racks$\}$ symbolic;

param agv$\_$location$\{$AGVs$,$ Axes$\}$ symbolic;

param agv$\_$status$\{$AGVs$\}$ symbolic;

param workstation$\_$location$\{$Workstations$\}$ symbolic;

param sku$\_$inventory$\{$Racks$,1.\mathrm{.}10\}>=0$;

param demands$\{$Workstations$,1.\mathrm{.}40\}>=0$;

param berths$\{$Workstations$\}>=0$;

# Decision variables

var AssignRackToAGV$\{$Racks$,$ AGVs$\}$ binary;

var AssignRackToWorkstation$\{$Racks$,$ Workstations$\}$ binary;

# Objective function

param alpha$1$ :$=1$; # Weight for rack$-$AGV distance

param alpha$2$ :$=1\mathrm{.}3$; # Weight for rack$-$workstation distance

param alpha$3$ :$=1$; # Weight for unfulfilled orders

minimize TotalDistance:

alpha$1*$ sum$\{$r in Racks, a in AGVs, ax in Axes$\}$ AssignRackToAGV$[$r$,$ a$]*$ abs$($rack$\_$location$[$r$,$ ax$]-$ agv$\_$location$[$a$,$ ax$])+$

alpha$2*$ sum$\{$r in Racks, w in Workstations, ax in Axes$\}$ AssignRackToWorkstation$[$r$,$ w$]*$ abs$($rack$\_$location$[$r$,$ ax$]-$ workstation$\_$location$[$w$])+$

alpha$3*$ sum$\{$w in Workstations, sku in $1.\mathrm{.}40\}$ max$(0,$ demands$[$w$,$ sku$]-$ sum$\{$r in Racks$\}$ AssignRackToWorkstation$[$r$,$ w$]*$ sku$\_$inventory$[$r$,$ sku$])$;

# Constraints

subject to RackAssignmentConstraint:

forall$\{$r in Racks$\}$ sum$\{$a in AGVs$\}$ AssignRackToAGV$[$r$,$ a$]=1$;

subject to WorkstationAssignmentConstraint:

forall$\{$r in Racks$\}$ sum$\{$w in Workstations$\}$ AssignRackToWorkstation$[$r$,$ w$]=1$;

subject to BerthConstraint$\{$w in Workstations$\}$:

sum$\{$r in Racks$\}$ AssignRackToWorkstation$[$r$,$ w$]<=$ berths$[$w$]$;

$````````````````````````````$

$.$dat;

set Racks :$=$ R$1..$ R$80$;

param rack$\_$location: $"$x$""$y$"$:$=$

R$1103$

R$2105$

Up to $...$

R$804041$;

param rack$\_$status:$=$

R$1$ "stationary"

R$2$ "stationary"

R$3$ "stationary"

R$4$ "stationary"

R$5$ "stationary"

R$6$ "stationary"

R$7$ "stationary"

R$8$ "stationary"

R$9$ "stationary"

R$10$ "stationary"

R$11$ "stationary"

R$12$ "stationary"

R$13$ "AGV$7"$

R$14$ "stationary"

R$15$ "stationar"

Up to $...$

R$80$ "stationary"

;

set AGVs :$=$ A$1..$ A$20$;

param agv$\_$location:"x$""$y$"$:$=$

A$11522$

A$291$

Up to $...$

A$20421$

;

param agv$\_$status:$=$

AGV$1$ "active"

AGV$2$ "idle"

Up to $...$

AGV$20$ "idle"

;

set Workstations:$=$ W$1$ W$2$ W$3$ W$4$;

param workstation$\_$location:$=$

W$1"00"$

W$2"050"$

W$3"500"$

W$4"5050"$

;

param sku$\_$inventory: S$1$ S$2$ S$3$ S$4$ S$5$ S$6$ S$7$ S$8$ S$9$ S$10$ S$11$ S$12$ S$13$ S$14$ S$15$ S$16$ S$17$ S$18$ S$19$ S$20$ S$21$ S$22$ S$23$ S$24$ S$25$ S$26$ S$27$ S$28$ S$29$ S$30$ S$31$ S$32$ S$33$ S$34$ S$35$ S$36$ S$37$ S$38$ S$39$ S$40$:$=$

R$17519201392101014000000000000000000000000000000$

R$22015111183961514000000000000000000000000000000$

R$328114111463114000000000000000000000000000000$

Up to $...$

R$80000000000000000000000000019261870000016186412$;

param demands: S$1$ S$2$ S$3$ S$4$ S$5$ S$6$ S$7$ S$8$ S$9$ S$10$ S$11$ S$12$ S$13$ S$14$ S$15$ S$16$ S$17$ S$18$ S$19$ S$20$ S$21$ S$22$ S$23$ S$24$ S$25$ S$26$ S$27$ S$28$ S$29$ S$30$ S$31$ S$32$ S$33$ S$34$ S$35$ S$36$ S$37$ S$38$ S$39$ S$40$:$=$

W$11613110119171326211424221943506203046402642827316217360060213223$

W$2293249148111461422420104593514423161112638514322212173019191$

W$3231281101580036180222313224027648913244201093645234662027224117$

W