diff --git a/ora/flex_ws_api.pkb b/ora/flex_ws_api.pkb
index eea66d9..a2012a3 100755
--- a/ora/flex_ws_api.pkb
+++ b/ora/flex_ws_api.pkb
@@ -260,6 +260,7 @@ is
     l_hdr_value     varchar2(1024);
     l_hdr           header;
     l_hdrs          header_table;
+    l_returnvalue   xmltype;
 begin
 
     -- determine database characterset, if not AL32UTF8, conversion will be necessary
@@ -389,13 +390,17 @@ begin
     end;
 
     utl_http.end_response(l_http_resp);
+    
+    begin
+        l_returnvalue := xmltype.createxml( l_clob );
+    exception when others then
+        if sqlcode = -31011 then -- invalid xml
+            raise_application_error( -20001, 'HTTP response could not be converted to XML. Response was (first 1000 characters): ' || dbms_lob.substr( l_clob, 1000 ));
+        end if;
+    end;
+    dbms_lob.freetemporary( l_clob );
 
-    return xmltype.createxml(l_clob);
-
-exception when others then
-    if sqlcode = -31011 then -- its not xml
-        return null;
-    end if;
+    return l_returnvalue;
 end make_request;
 
 function make_rest_request(
diff --git a/ora/xlsx_builder_pkg.pkb b/ora/xlsx_builder_pkg.pkb
index 8f4ad26..31345fd 100755
--- a/ora/xlsx_builder_pkg.pkb
+++ b/ora/xlsx_builder_pkg.pkb
@@ -1,5 +1,5 @@
 CREATE OR REPLACE package body xlsx_builder_pkg
-as
+as 
 --
   c_LOCAL_FILE_HEADER        constant raw(4) := hextoraw( '504B0304' ); -- Local file header signature
   c_END_OF_CENTRAL_DIRECTORY constant raw(4) := hextoraw( '504B0506' ); -- End of central directory signature
@@ -1624,9 +1624,9 @@ ts timestamp := systimestamp;
       loop
         t_xxx := t_xxx || '<autoFilter ref="' ||
             alfan_col( nvl( workbook.sheets( s ).autofilters( a ).column_start, t_col_min ) ) ||
-            nvl( workbook.sheets( s ).autofilters( a ).row_start, workbook.sheets( s ).rows.first() ) || ':' ||
+            to_char( nvl( workbook.sheets( s ).autofilters( a ).row_start, workbook.sheets( s ).rows.first() )) || ':' ||
             alfan_col( coalesce( workbook.sheets( s ).autofilters( a ).column_end, workbook.sheets( s ).autofilters( a ).column_start, t_col_max ) ) ||
-            nvl( workbook.sheets( s ).autofilters( a ).row_end, workbook.sheets( s ).rows.last() ) || '"/>';
+            to_char( nvl( workbook.sheets( s ).autofilters( a ).row_end, workbook.sheets( s ).rows.last() )) || '"/>';
       end loop;
       if workbook.sheets( s ).mergecells.count() > 0
       then
@@ -1694,7 +1694,7 @@ ts timestamp := systimestamp;
       t_xxx := t_xxx || '<pageMargins left="0.7" right="0.7" top="0.75" bottom="0.75" header="0.3" footer="0.3"/>';
       if workbook.sheets( s ).comments.count() > 0
       then
-        t_xxx := t_xxx || '<legacyDrawing r:id="rId' || ( workbook.sheets( s ).hyperlinks.count() + 1 ) || '"/>';
+        t_xxx := t_xxx || '<legacyDrawing r:id="rId' || to_char( workbook.sheets( s ).hyperlinks.count() + 1 ) || '"/>';
       end if;
 --
       t_xxx := t_xxx || '</worksheet>';
@@ -1949,6 +1949,7 @@ style="position:absolute;margin-left:35.25pt;margin-top:3pt;z-index:' || to_char
       then
         dbms_sql.close_cursor( t_c );
       end if;
+    raise;
   end;
 end xlsx_builder_pkg;
 /
diff --git a/ora/xlsx_builder_pkg.pks b/ora/xlsx_builder_pkg.pks
index 67f922e..bf656d0 100755
--- a/ora/xlsx_builder_pkg.pks
+++ b/ora/xlsx_builder_pkg.pks
@@ -1,5 +1,5 @@
 create or replace package xlsx_builder_pkg
-as
+authid current_user as
 /**********************************************
 **
 ** Author: Anton Scheffer