Trying to get full first and last names of ClearQuest users from a certain group

Nowhere in the script, I believe that's what this is doing:
     # tell it which group to pull from
      my $group_BS = "Business";
    # populate the choicelist from the above group
    &UserChoiceLists($fieldname, $group_BS);
   # sort the choicelist
      @choices = sort @returnchoices;
  # return the sorted choicelist from the group specified
    return @choices;

Here's what those lines are doing:

      my $group_BS = "Business";

Declares a variable $group_BS, scoped to the current sub function, and assigns it the value "Business"

    &UserChoiceLists($fieldname, $group_BS);

Calls the subfunction UserChoiceLists(), passing to it the scalar variables $fieldname and $group_BS.

      @choices = sort @returnchoices;

Populates a locally scoped empty array declared earlier in the sub function with the result of sorting a mystery and possibly empty array called @returnchoices.

    return @choices;

The subfunction ends, returning the possibly empty array @choices to whatever part of the script called the function to begin with.

You really need to track down the origin of @returnchoices.  Where is it declared (likely with the "my" keyword)?  Where else in the script does @returnchoices appear?

Maybe this will be easier to work off of, I get the same result... I thought the commented out parts would work, but I get an error.

sub bus_sponser_ChoiceList {
    my($fieldname) = @_;
    my @choices;
    my $group_BS = "Business";
    foreach $item (&UserChoiceLists($fieldname, $group_BS)) {
    # $userFullname = $item->GetFullName();
    if ($item ne "") {
     push(@choices, $item);
     # push(@choices, $userFullname)
    }
   }
    return @choices;
}

Does UserChoiceLists return an array?  If so, the first post from mjcoyne should work.  If not, then there is nothing to loop on.

Can you post the code for UserChoiceLists?

Here's my updated mess, I mean code:  Getting the following error message:

ERROR! Execution of a hook failed during the action Submit.  It was the FIELD_CHOICE_LIST hook of the field bus_sponsor, attached to the ChangeRequest "mydb00000083".  The reason for the failure was: ST(1) does not contaion a reference. at C:/Program Files/Rational/common/lib/perl4/site_perl/5.8.6/CQPerlExt.pm line 43.

sub bus_sponser_ChoiceList {
    my($fieldname) = @_;
    my @choices;
    $session = $entity->GetSession();
    my $group_BS = "Business";
    my $variable = "";
    foreach $item (&UserChoiceLists($fieldname, $group_BS)) {
    if (length($variable) > 0) {
      $variable = "$variable,$item";
      } else {
      $variable = "$item";
      }
     }
     my @users = split(/,/, $variable);
     $querydef = $session->BuildQuery("users");
     $querydef->BuildField("fullname");
     $querydef->BuildField("email");
     $operator = $querydef->BuildFilterOperator($CQPerlExt::CQ_BOOL_OP_OR);
     $operator->BuildFilter("fullname", $CQPerlExt::CQ_COMP_OP_EQ, \@users);
     $operator->BuildFilter("login_name", $CQPerlExt::CQ_COMP_OP_EQ, \@users );
     $resultset = $session->BuildResultSet(querydef);
     $resultSet->Execute;

     $status = $resultSet->MoveNext;
     my $fullnames = "";
     while ( $status == $CQPerlExt::CQ_SUCCESS ) {    
     $names = "";
     $names = $resultset->GetColumnValue(1);
     if (length($fullnames) > 0) {
      $fullnames = "$fullnames,$names";
      } else {
      $fullnames = "$names";
      }
      $status    = $resultset->MoveNext();
     }

     my @userfnames = split(/,/, $fullnames);
     @choices = sort @userfnames;
     return @choices;
}

Or try this:

use Data::Dumper;    #Put this at the top of the script

my @Returns=&UserChoiceLists($fieldname, $group_BS);
print Data::Dumper->Dump([\@Returns], ['UserChoiceLists return value']);

finally found it:

sub UserChoiceLists {      
      my($fieldname, $groups) = @_; #Strings from field script
      @group = split /,/,$groups;   #String to an array
      @returnchoices = ();               #Creating a blank array
      $session = $entity->GetSession();
    $session->OutputDebugString("ENTERING: GlobalScripts::AssignmentForm_fieldChanged\n");
    $cqquery = $session->BuildQuery("users");
      $cqquery->BuildField("login_name");
    $cqfilter = $cqquery->BuildFilterOperator($CQPerlExt::CQ_BOOL_OP_AND);
    $cqfilter->BuildFilter("groups.name", $CQPerlExt::CQ_COMP_OP_IN, \@group );
    $resultset = $session->BuildResultSet($cqquery);
    $resultset->Execute();

    $movenext = $resultset->MoveNext();
    while ($movenext == $CQPerlExt::CQ_SUCCESS) {
            my $loginname = $resultset->GetColumnValue(1);
            $session->OutputDebugString("loginname  = $loginname\n");
            push @returnchoices, $loginname;
            $movenext = $resultset->MoveNext();
      }
      return @returnchoices;
 }