iwcallback doesn't work after a post

System

I'm trying to create a workflow starting with an immediate cgitask. I want to have it post some form data to the cgi program and also have a button to do a callback to a successor. It works except for when the post has occurred to my own cgi. After that the callback doesn't happen and the window doesn't close.
I'm using TeamSite 5.5.2 on Windows and ie 5.0 for a browser.
I've tried several things including using iw_cgi_wrapper.cgi, but it comes down to the javascript that posts to iwcallback.cgi doesn't cause the window to close or the next task to activate.
Here's my wft and the cgi program it is calling.

<?xml version="1.0" standalone="no"?>
<!DOCTYPE workflow SYSTEM "../iwwf.dtd">
<!-- ============================================================ -->

<workflow name="CGITest"
owner="__TAG__('iw_user');"
creator="__TAG__('iw_user');"
description="Try to post to cgi, then do a callback to successor">

<template_script><![CDATA[
# Import routines from library
use TeamSite::Usertask qw(
cleanup_paths
get_names_from_file
get_mail_cmd
make_branchpathlist
);

######################################################################
# Name: set_area
# Args: btag - TAG_info variable name for branch path.
# watag - TAG_info variable name for workarea.
# Usage: ($a, $b, $w, $s) = set_area("$btag", "$watag");
# Purpose: If the built-in variables for branch and workarea have
# not been set, pull the information from the workflow
# instantiation form (using the btag and watag info).
# Use the branch and workarea information to generate
# a valid areavpath (using a library routine)
# Returns: Returns the generated areavpath, the branch path, the
# workarea name, and a boolean indicating whether or not
# the branch and workarea need to be prompted for during
# instantiation (this relies on the fact that this code
# is run multiple times during the instantion process).
######################################################################
sub set_area{
my($btag, $watag) = @_;
my($avpath, $bpath, $wapath, $skip);
my($iwbpath, $iwwapath) = (__VALUE__("iw_branch"),
__VALUE__("iw_workarea"));
if ((length($iwbpath)) > 0 && (length($iwwapath)) > 0){
$bpath = $iwbpath;
($wapath = $iwwapath) =~ s|^\s*/.*|;
$wapath =~ s|/\s*$||;
return("$wapath", "$iwbpath", "$wapath", "TRUE");
}
($bpath, $wapath, $avpath) = cleanup_paths(__VALUE__("$btag"),
__VALUE__("$watag"));
return("$avpath", "$bpath", "$wapath", "FALSE");
}

my($area_vpath, $branch_path, $work_area, $skip_branch) =
set_area("branch_path", "work_area");

#======================================================================
# JOB FORM DATA CAPTURE
#---------------------------------------------------------------------
# This section capture the necessary data on the job creation form in
# order to dynamically assemble a workflow.
#======================================================================
sub debug{
TAG_info(
iw_output_file => "<input type='text' value='/tmp/foo.xml'>",
iw_debug_mode =>
"<input type='radio' value='true'>True</input>" .
"<input type='radio' value='false'>False</input>",
);
}
#======================================================================
# Uncomment following line if you wish to enable workflow debugging.
#======================================================================
#&debug;

#=====================================================================
# XML JOB SPECIFICATION SKELETON
#=====================================================================
# This XML section is used to generate the job specification files based on
# input provided by the end-user in the job creation form.
]]></template_script>

<cgitask name="CreateCGIForm"
owner="__TAG__('iw_user');"
description="Create a form to post to" start="t" immediate="t">
<areavpath v='__INSERT__($area_vpath);'/>
<successors>
<successorset description="_Done">
<succ v='End'/>
</successorset>
</successors>
<command v="cgitest.cgi"/>
</cgitask>


<!-- =========================== End ============================= -->

<endtask name='End'>
</endtask>

<!-- ============================================================= -->

</workflow>

#!c:\teamsite\iw-perl\bin\iwperl
use TeamSite::CGI_lite;
use TeamSite:CRparser;
use TeamSite::WFtask;
use strict;

my $cgi = TeamSite::CGI_lite->new();
$cgi->parse_data();
my $testfield1 = $cgi->{form}{testfield1};
my $testfield2 = $cgi->{form}{testfield2};
my $branch;
if (! ref $cgi->{form}{area_path}) {
$branch = $cgi->escape_html_data($cgi->{form}{area_path});
}
else {
$branch = TeamSite::CGI_lite->escape_html_data($cgi->{form}{area_path}[0]);
}

my @exclude = ('testfield1','testfield2'); # this is emitted explicitly by our CGI

# grab everything else and html-tunnelize it

my $other_tunneled_data = $cgi->get_implicit_data_tunnel_html(@exclude);

my ($task_id,$task);
if (defined $cgi->{form}{done}) {
$cgi->iwcallback("_Done","End of test");
}
else {

print<<"END";
Content-type: text/html

<html><head><title>Test CGI Post</title></head>
<form name="MyForm" method="POST" action="/iw-bin/iw_cgi_wrapper.cgi/cgitest.cgi">
<center>Branch: $branch</center>
field1: <input type="text" name="testfield1" value="$testfield1" /><br>
field2: <input type="text" name="testfield2" value="$testfield2" /><br>

END

print $other_tunneled_data;

if ( $testfield1 ne "" && $testfield2 ne "") {
print "Data posted: " . $testfield1 . " " . $testfield2 . "<br>";
}

print "<center><input type=\"submit\" value=\"Post Form\" name=\"submit\">";
print "</form><form name=\"mainform\" method=\"POST\" action=\"/iw-bin/iw_cgi_wrapper.cgi/cgitest.cgi\">";
print $other_tunneled_data;
print "<center><input type=\"submit\" value=\"Done\" name=\"done\">";

print<<"END";
</form>
</body>
</html>

END
}