fixed warnings in error_log for .config.php file

SE/.config.php

@@ -331,10 +331,10 @@ $special_tables_ignore_init=array('L_APPOITMENT','BILLS_FVAT_2'); //tabele, ktor
 
 
 
-$CNF_ZASOB['14']['INTERFACE_ADDR'] = $INTERFACE_ADDR;
-$CNF_ZASOB['14']['SQL_USER'] = $SQL_USER;
-$CNF_ZASOB['14']['SQL_USER_PASS'] = $SQL_USER_PASS;
-$CNF_ZASOB['14']['SQL_DATABASE'] = $SQL_DATABASE; 
+$CNF_ZASOB['14']['INTERFACE_ADDR'] = (isset($INTERFACE_ADDR))? $INTERFACE_ADDR : null;
+$CNF_ZASOB['14']['SQL_USER'] = (isset($SQL_USER))? $SQL_USER : null;
+$CNF_ZASOB['14']['SQL_USER_PASS'] = (isset($SQL_USER_PASS))? $SQL_USER_PASS : null;
+$CNF_ZASOB['14']['SQL_DATABASE'] = (isset($SQL_DATABASE))? $SQL_DATABASE : null;