Forum .LRN Q&A: Error creating subgroups in dotLRN

I have a problem when I'm trying to create a new subgroup from Admin page within a Community in dotLRN 2.2.0.

After typing the subgroup name I see the next message:

selection did not return a value, and no default was provided
while executing
"db_string select_st_id {}"
(procedure "dotlrn::apm::after_instantiate" line 15)
invoked from within
"dotlrn::apm::after_instantiate -package_id 21347"
("eval" body line 1)
invoked from within
"eval $command"
(procedure "apm_invoke_callback_proc" line 37)
invoked from within
"apm_invoke_callback_proc -package_key $package_key -type "after-instantiate" -arg_list [list package_id $package_id]"
(procedure "apm_package_instance_new" line 17)
invoked from within
"apm_package_instance_new -package_id $package_id -package_key $package_key -instance_name $package_name -context_id $context_id"
(procedure "site_node::instantiate_and_mount" line 39)
invoked from within
"site_node::instantiate_and_mount -parent_node_id $parent_node_id -node_name $community_key -package_key [one_community_package_key] -package_name ..."
invoked from within
"set package_id [site_node::instantiate_and_mount -parent_node_id $parent_node_id -node_name $community_key -package_key [one_community_package_key]..."
("uplevel" body line 40)
invoked from within
"uplevel 1 $transaction_code "
(procedure "db_transaction" line 39)
invoked from within
"db_transaction {
set user_id [ad_conn user_id]
set community_id [package_instantiate_object -extra_vars $extra_vars $object_ty..."
(procedure "dotlrn_community::new" line 26)
invoked from within
"dotlrn_community::new -parent_community_id $parent_community_id -description $description -community_type dotlrn_community -pretty_name $pretty_na..."
invoked from within
"set subcomm_id [dotlrn_community::new -parent_community_id $parent_community_id -description $description -community_type dotlrn_community -pretty..."
("uplevel" body line 2)
invoked from within
"uplevel 1 $transaction_code "
(procedure "db_transaction" line 39)
invoked from within
"db_transaction {
set subcomm_id [dotlrn_community::new -parent_community_id $parent_community_id -description $description -community_type ..."
invoked from within
"if {[form is_valid add_subcomm]} {
form get_values add_subcomm pretty_name description join_policy referer

# we set some extra vars based on..."
("uplevel" body line 57)
invoked from within
"uplevel {
#
# Copyright (C) 2001, 2002 MIT
#
# This file is part of dotLRN.
#
# dotLRN is free software; you can redistribute it and/or modify it u..."
(procedure "code::tcl::/var/lib/aolserver/openabayval/packages/dotlrn/ww..." line 2)
invoked from within
"code::tcl::$__adp_stub"
invoked from within
"if { [file exists $__adp_stub.tcl] } {

# ensure that data source preparation procedure exists and is up-to-date
adp_init tcl $__adp_stub
..."
("uplevel" body line 3)
invoked from within
"uplevel {

if { [file exists $__adp_stub.tcl] } {

# ensure that data source preparation procedure exists and is up-to-date
adp_init t..."
(procedure "adp_prepare" line 2)
invoked from within
"adp_prepare "
(procedure "template::adp_parse" line 30)
invoked from within
"template::adp_parse [file root [ad_conn file]] {}"
(procedure "adp_parse_ad_conn_file" line 5)
invoked from within
"$handler"
("uplevel" body line 2)
invoked from within
"uplevel $code"
invoked from within
"ad_try {
$handler
} ad_script_abort val {
# do nothing
}"
invoked from within
"rp_serve_concrete_file [ad_conn file]"
(procedure "rp_serve_abstract_file" line 60)
invoked from within
"rp_serve_abstract_file "$root/$path""
("uplevel" body line 2)
invoked from within
"uplevel $code"
invoked from within
"ad_try {
rp_serve_abstract_file "$root/$path"
set tcl_url2file([ad_conn url]) [ad_conn file]
set tcl_url2path_info..."

Any suggestion?