** Using WeBWorK **

This doesn't solve the issues you had above, but this is a bit of code that I had written to print out the scores for all students for a given homework set in a given class. Perhaps it is something that you can modify for your own needs.

---

#!/usr/bin/perl

#########################################
#
#  Values for course and set
#

my $courseID = "12FA-MTH115-01_02";
my $setID = "Week5";


#########################################

BEGIN {
  unless ($ENV{WEBWORK_ROOT}) {
    $ENV{WEBWORK_ROOT} = "/WeBWorK/webwork2";
  }
}

use lib "$ENV{WEBWORK_ROOT}/lib";
use WeBWorK::CourseEnvironment;
use WeBWorK::DB;

#########################################
#
#  Get course environment
#
our $ce = WeBWorK::CourseEnvironment->new({
  webwork_dir => $ENV{WEBWORK_ROOT},
  courseName => $courseID,
});
our $db = WeBWorK::DB->new($ce->{dbLayout});


#
#  Get problems
#
my @problemIDs = $db->listGlobalProblems($setID);

#
#  Get list of users
#
my %users;
foreach my $user ($db->getUsers($db->listUsers)) {
  next unless $user && $user->section ne "Practice";
  $users{$user->user_id} = $user
    if $ce->status_abbrev_has_behavior($user->status,"include_in_scoring");
}

#
#  Sort users and print out scores for those who have taken the exam
#
foreach my $user (sort {
  lc($users{$a}->last_name)  cmp lc($users{$b}->last_name) ||
  lc($users{$a}->first_name) cmp lc($users{$b}->first_name) ||
  lc($users{$a}->user_id)    cmp lc($users{$b}->user_id)
} keys %users) {
  my $User = $users{$user};
  my $score = 0; my $attempts = 0;
  my %problems = (map {$_->problem_id => $_} $db->getAllMergedUserProblems($user, $setID));
  foreach my $id (@problemIDs) {
    my $Problem = $problems{$id};
    $score += $Problem->status * $Problem->value;
    $attempts++ if ($Problem->num_correct || 0) + ($Problem->num_incorrect || 0);
  }
  print $User->last_name.", ".$User->first_name." (".$User->user_id."): ".sprintf("%.1f",$score)."\n"
    if $attempts;
}

#########################################

1;

I got the same error when I tried to run your script on my CentOS 6 system (a RedHat clone).  I was able to get it to run without errors by adding

For the record, here is another version of my program that handles Gateway Quiz assignments as well as homework assignments. For gateway quizzes, it prints out the score on each version of the quiz for each student.

Davide

---

#!/usr/bin/perl

#########################################
#
#  Values for course and set
#

my $courseID = "dpvc-test";
my $setID = "Gateway1";


#########################################

BEGIN {
  unless ($ENV{WEBWORK_ROOT}) {
    $ENV{WEBWORK_ROOT} = "/WeBWorK/webwork2";
  }
}

use lib "$ENV{WEBWORK_ROOT}/lib";
use WeBWorK::CourseEnvironment;
use WeBWorK::DB;

#########################################
#
#  Get course environment
#
our $ce = WeBWorK::CourseEnvironment->new({
  webwork_dir => $ENV{WEBWORK_ROOT},
  courseName => $courseID,
});
our $db = WeBWorK::DB->new($ce->{dbLayout});


#
#  Get set data and problems
#
my $globalSet = ($db->getGlobalSets($setID))[0];
my $isGateway = $globalSet->assignment_type =~ /gateway/i;
my @problemIDs = $db->listGlobalProblems($setID);

#
#  Get list of users
#
my %users;
foreach my $user ($db->getUsers($db->listUsers)) {
  next unless $user && $user->section ne "Practice";
  $users{$user->user_id} = $user
    if $ce->status_abbrev_has_behavior($user->status,"include_in_scoring");
}

#
#  Sort users and print out scores for those who have attempted the set
#
foreach my $user (sort {
  lc($users{$a}->last_name)  cmp lc($users{$b}->last_name) ||
  lc($users{$a}->first_name) cmp lc($users{$b}->first_name) ||
  lc($users{$a}->user_id)    cmp lc($users{$b}->user_id)
} keys %users) {
  my $User = $users{$user};
  my $scores = ($isGateway ? getGatewayScores($user,$setID) : getHomeworkScore($user,$setID));
  if (scalar(@$scores)) {
    my $score = join(', ',map {sprintf("%.1f",$_)} @$scores);
    print $User->last_name.", ".$User->first_name." (".$User->user_id."): $score\n";
  }
}

#########################################
#
#  Compute the scores for all versions of a gateway test
#
sub getGatewayScores {
  my $user = shift; my $setID = shift;
  my @scores = ();
  foreach my $v ($db->listSetVersions($user,$setID)) {
    my $score = 0; my $attempts = 0;
    my @records = $db->getProblemVersions(map {[$user,$setID,$v,$_]} @problemIDs);
    foreach $Problem (@records) {
      $score += $Problem->status * $Problem->value;
      $attempts++ if ($Problem->num_correct || 0) + ($Problem->num_incorrect || 0);
    }
    push(@scores,$score) if $attempts;
  }
  return [@scores];
}

#########################################
#
#  Compute the score for a homework set
#
sub getHomeworkScore {
  my $user = shift; my $setID = shift;
  my $score = 0; my $attempts = 0;
  my %problems = (map {$_->problem_id => $_} $db->getAllMergedUserProblems($user, $setID));
  foreach my $id (@problemIDs) {
    my $Problem = $problems{$id};
    if ($Problem) {
      $score += $Problem->status * $Problem->value;
      $attempts++ if ($Problem->num_correct || 0) + ($Problem->num_incorrect || 0);
    }
  }
  return ($attempts ? [$score] : []);
}

#########################################

1;