diff --git a/htdocs/compta/tva/index.php b/htdocs/compta/tva/index.php
index 1d6148c40a3..d2e400f25e4 100644
--- a/htdocs/compta/tva/index.php
+++ b/htdocs/compta/tva/index.php
@@ -142,13 +142,13 @@ for ($m = 1 ; $m < 13 ; $m++ )
 	$coll_listsell = vat_by_date($db, $y, 0, 0, 0, $modetax, 'sell', $m);
 	$coll_listbuy = vat_by_date($db, $y, 0, 0, 0, $modetax, 'buy', $m);
 
-	if ($coll_listbuy == -1)
+	if (! is_array($coll_listbuy) && $coll_listbuy == -1)
 	{
 		$langs->load("errors");
 		print '<tr><td colspan="5">'.$langs->trans("ErrorNoAccountancyModuleLoaded").'</td></tr>';
 		break;
 	}
-	if ($coll_listbuy == -2)
+	if (! is_array($coll_listbuy) && $coll_listbuy == -2)
 	{
 		print '<tr><td colspan="5">'.$langs->trans("FeatureNotYetAvailable").'</td></tr>';
 		break;
diff --git a/htdocs/lib/tax.lib.php b/htdocs/lib/tax.lib.php
index f496321469f..1df85550a64 100644
--- a/htdocs/lib/tax.lib.php
+++ b/htdocs/lib/tax.lib.php
@@ -270,7 +270,7 @@ function vat_by_date($db, $y, $q, $date_start, $date_end, $modetax, $direction,
 	if ($sql && $sql=='TODO') return -2;
 	if ($sql && $sql!='TODO')
 	{
-		dol_syslog("Tax.lib.php::vat_by_quarter sql=".$sql);
+		dol_syslog("Tax.lib.php::vat_by_date sql=".$sql);
 
 		$resql = $db->query($sql);
 	    if ($resql)
@@ -399,11 +399,15 @@ function vat_by_date($db, $y, $q, $date_start, $date_end, $modetax, $direction,
 		}
     }
 
-	if (! $sql) return -1;
-	if ($sql && $sql=='TODO') return -2;
+	if (! $sql)
+	{
+		dol_syslog("Tax.lib.php::vat_by_date no accountancy module enabled".$sql,LOG_ERR);
+		return -1;	// -1 = Not accountancy module enabled
+	}
+	if ($sql && $sql=='TODO') return -2; // -2 = Feature not yet available
 	if ($sql && $sql!='TODO')
 	{
-		dol_syslog("Tax.lib.php::vat_by_quarter sql=".$sql);
+		dol_syslog("Tax.lib.php::vat_by_date sql=".$sql);
 	    $resql = $db->query($sql);
 	    if ($resql)
 	    {