diff --git a/manifests/params.pp b/manifests/params.pp
index 9b1cd2c..35f9668 100644
--- a/manifests/params.pp
+++ b/manifests/params.pp
@@ -180,15 +180,15 @@ class postgresql::params inherits postgresql::globals {
       $server_package_name  = pick($server_package_name, "postgresql${version}-server")
       $contrib_package_name = pick($contrib_package_name, "postgresql${version}-contrib")
       $devel_package_name   = pick($devel_package_name, "postgresql${version}-devel")
-      $java_package_name    = pick($java_package_name, 'undef')
-      $perl_package_name    = pick($plperl_package_name, 'undef')
-      $plperl_package_name  = pick($plperl_package_name, "undef")
-      $python_package_name  = pick($python_package_name, 'undef')
+      $java_package_name    = pick($java_package_name, undef)
+      $perl_package_name    = pick($plperl_package_name, undef)
+      $plperl_package_name  = pick($plperl_package_name, undef)
+      $python_package_name  = pick($python_package_name, undef)
 
       $service_name         = pick($service_name, 'postgresql')
       $bindir               = pick($bindir, "/usr/lib/postgresql${version}/bin")
       $datadir              = pick($datadir, '/var/lib/pgsql/data')
-      $confdir              = pick($confdir, "${datadir}")
+      $confdir              = pick($confdir, $datadir)
       $service_status       = pick($service_status, "/etc/init.d/${service_name} status")
       $psql_path            = pick($psql_path, "${bindir}/psql")