HELP : different behaviour between midgard 1.5 and 1.7

hello, 
I'm trying to migrate pieces of software from midgard 1.5 to midgard 1.7. 

Php functions are split into 2 page elements : 
//-------------------------------------------------------
Pageelement named "code-global" contains mysql low level access functions : 
  
//*** DB Connexion to server
Function db_connect($BDD=""){
  global $Host,$User,$Password,$DBname;
  $dbh = @mysql_pconnect($Host,$User,$Password)
  or erreur("Connnexion au serveur de données $host impossible");
  
  if($BDD!=""){
    // Selection de la base 
    @mysql_select_db($BDD)
    or erreur("Selection de la base impossible");
  }else{
    // Selection de la base 
    @mysql_select_db($DBname)
    or erreur("Selection de la base impossible");
  }
  return $dbh;

}

//** DB query function 
Function requete($query)
{
  global  $DBname;
  @mysql_select_db($DBname);
    
  if ($resultat = mysql_query($requete)) return $resultat;
  else erreur("Erreur dans la demande : $requete<BR>".mysql_error());
}  common_function contains display func : 
  
//--------------------------------------------------
Pageelement named "common_functions" contains display functions
//display result
Function my_display_func($pTable){

// connexion to DB
  if (!($dbh=db_connect($pDB))) 
    erreur ("empty handle ");
  
// run query 
$o_resultat2=requete($st_requete);

... 
}


when calling my_diplay_func("testTable") from a page
error occured when proceeding request : 
  Warming : mysql_query(): Access denied for user: 'www-data@localhost' (Using password: NO) in /usr/lib/apache2/modules/midgard-root-nommp.php(41) : eval()'d code on line 159
  Warning: mysql_query(): A link to the server could not be established in /usr/lib/apache2/modules/midgard-root-nommp.php(41) : eval()'d code on line 159


this error occurs since i moved from midgard 1.5 to 1.7. 
never met such issue on 1.5.

will be pleased to investigate any ideas. 
Thx 
JY