I'd a problem of lost informations between two parses of PHP.

In the first parse, I'd a clean session which looks like this :
----------------------
data_ticker|a:2:{i:0;O:16:"newslist_indices":7:{s:5:"TITLE";s:9:"ACCOR STK";s:4:"LAST";s:5:"46.88";s:4:"CHGT";s:4:"1.39";s:4:"PRCT";s:4:"3.06";s:8:"EXCHANGE";s:10:"SBF       ";s:3:"URL";s:60:"http://www.cityquote.com/bmp/data_details.php?index_id=43232";s:11:"PUBLISHDATE";s:12:"26/04/2001  ";}i:1;O:16:"newslist_indices":7:{s:5:"TITLE";s:15:"AIR LIQUIDE STK";s:4:"LAST";s:5:"162.3";s:4:"CHGT";s:4:"-0.4";s:4:"PRCT";s:5:"-0.25";s:8:"EXCHANGE";s:10:"SBF       ";s:3:"URL";s:60:"http://www.cityquote.com/bmp/data_details.php?index_id=43233";s:11:"PUBLISHDATE";s:12:"26/04/2001  ";}}
-----------------------

And then after the second parse (after of course a 'session_start()'), the session looks like this :
----------------------
data_ticker|a:2:{i:0;O:16:"newslist_indices":8:{s:5:"TITLE";s:9:"ACCOR STK";s:4:"LAST";s:5:"46.88";s:4:"CHGT";s:4:"1.39";s:4:"PRCT";s:4:"3.06";s:8:"EXCHANGE";s:10:"SBF       ";s:3:"URL";s:60:"http://www.cityquote.com/bmp/data_details.php?index_id=43232";s:11:"PUBLISHDATE";s:12:"26/04/2001  ";}i:1;O:16:"newslist_indices":8:{s:5:"TITLE";s:15:"AIR LIQUIDE STK";s:4:"LAST";s:5:"162.3";s:4:"CHGT";s:4:"-0.4";s:4:"PRCT";s:5:"-0.25";s:8:"EXCHANGE";s:10:"SBF       ";s:3:"URL";s:60:"http://www.cityquote.com/bmp/data_details.php?index_id=43233";s:11:"PUBLISHDATE";s:12:"26/04/2001  ";}}
-----------------------

The only thing that changes is the number of properties had changed. It was 7 and then 8, thus, with a print_r functions, I've a "__PHP_Incomplete_Class Object" :

Array ( [0] => __PHP_Incomplete_Class Object ( [__PHP_Incomplete_Class_Name] => newslist_indices [TITLE] => ACCOR STK [LAST] => 46.88 [CHGT] => 1.39 [PRCT] => 3.06 [EXCHANGE] => SBF [URL] => http://www.cityquote.com/bmp/data_details.php?index_id=43232 [PUBLISHDATE] => 26/04/2001 ) [1] => __PHP_Incomplete_Class Object ( [__PHP_Incomplete_Class_Name] => newslist_indices [TITLE] => AIR LIQUIDE STK [LAST] => 162.3 [CHGT] => -0.4 [PRCT] => -0.25 [EXCHANGE] => SBF [URL] => http://www.cityquote.com/bmp/data_details.php?index_id=43233 [PUBLISHDATE] => 26/04/2001 ))

Austin.