D5 Multi-series line chart has wrong values and series

I'm plotting a Multi-series line chart using the API in Drupal5, but the values in the chart are not those I put in.
The chart I'm trying to become lists the last 30 days as categories and values for 'detail', 'info', 'send' and 'list' for series.

As you can see on the screenshot attached these values are not shown, not even all series are available (duplicates with wrong values are, but those are not very useful).
Upgrading to D6 is not possible, it would be too much work to port all custom modules.

Does anyone know what the problem may be?

Here's the contents of my data-array
07-17, detail, 2
07-17, send, 0
07-17, info, 0
07-17, list, 18
07-18, detail, 4
07-18, send, 0
07-18, info, 0
07-18, list, 21
07-19, detail, 1
07-19, send, 0
07-19, info, 0
07-19, list, 18
07-20, detail, 3
07-20, send, 0
07-20, info, 0
07-20, list, 16
07-21, detail, 9
07-21, send, 0
07-21, info, 0
07-21, list, 47
07-22, detail, 5
07-22, send, 0
07-22, info, 0
07-22, list, 29
07-23, detail, 2
07-23, send, 0
07-23, info, 0
07-23, list, 12
07-24, detail, 2
07-24, send, 0
07-24, info, 0
07-24, list, 20
07-25, detail, 6
07-25, send, 0
07-25, info, 0
07-25, list, 37
07-26, detail, 1
07-26, send, 0
07-26, info, 0
07-26, list, 16
07-27, detail, 5
07-27, send, 0
07-27, info, 0
07-27, list, 20
07-28, detail, 4
07-28, send, 0
07-28, info, 0
07-28, list, 20
07-29, detail, 8
07-29, send, 0
07-29, info, 0
07-29, list, 42
07-30, detail, 3
07-30, send, 0
07-30, info, 0
07-30, list, 16
07-31, detail, 2
07-31, send, 0
07-31, info, 0
07-31, list, 19
08-01, detail, 2
08-01, send, 0
08-01, info, 0
08-01, list, 20
08-02, detail, 10
08-02, send, 0
08-02, info, 0
08-02, list, 45
08-03, detail, 2
08-03, send, 0
08-03, info, 0
08-03, list, 23
08-04, detail, 6
08-04, send, 0
08-04, info, 0
08-04, list, 36
08-05, detail, 3
08-05, send, 0
08-05, info, 0
08-05, list, 24
08-06, detail, 1
08-06, send, 0
08-06, info, 0
08-06, list, 10
08-07, detail, 2
08-07, send, 0
08-07, info, 0
08-07, list, 22
08-08, detail, 6
08-08, send, 0
08-08, info, 0
08-08, list, 14
08-09, detail, 3
08-09, send, 0
08-09, info, 0
08-09, list, 41
08-10, detail, 7
08-10, send, 0
08-10, info, 0
08-10, list, 36
08-11, detail, 8
08-11, send, 0
08-11, info, 0
08-11, list, 41
08-12, detail, 4
08-12, send, 0
08-12, info, 0
08-12, list, 43
08-13, detail, 9
08-13, send, 0
08-13, info, 0
08-13, list, 47
08-14, detail, 9
08-14, send, 0
08-14, info, 0
08-14, list, 40
08-15, detail, 2
08-15, send, 0
08-15, info, 0
08-15, list, 5

code in callback function:

$type = 'Multi-series Line 2D';
$settings = array(
'Caption' => t('the caption')),
'DecimalPrecision' => 0,
'rotateNames' => 1
);
$attributes = array(
'callback' => 'Multi_series_Line_2D',
'callback_type' => FUSIONCHART_ARRAY,
'color' => array('00ff00', 'ff0000', '0000ff', '000000')
);
return array($ds_chart_data, $type, $settings, $attributes, 700, 300);