just downloaded and tried the previous release "v5.0.6 with two bug fixes". If anyone else gets the error
undefined function tep_hide_session_id

just edit catalogadminincludesfunctionsgeneral.php and add the following before the end

function tep_hide_session_id() {
global $session_started, $SID;

if (($session_started == true) && tep_not_null($SID)) {
return tep_draw_hidden_field(tep_session_name(), tep_session_id());
}
}


HTH

Si.

note: blank file attached

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