Fetching data into 'Lists of lists': HELP!!

I'm trying to create a graph with 'GD::Graph::lines'. To get the job done I need to fill a variable like this:

@data = (
[qw(09:00 09:05 09:10 09:15)],
[ (1.0, 1.4, -0.9, -0.4)],
);

When I fill in these example-values in the perl-script itself, it works fine and a nice graph is created.

However, my data are in a mysql-database, so I have to get them out of the database and into the variable '@data' in the required format (see above). One of the (many) things I tried, is to use a 'push' like this (in accordance with the PERLLOL(1)-manpage):

while (@row = $sth->fetchrow_array) {
push @data, $LoL["$time"][$value];
}

the $time and $value that are passed this way are:

09:00 1.0
09:05 1.4
09:10 -0.9
09:15 -0.4

It doesn't work! The module reports:
'Argument "09:00" isn't numeric in aelem at sample.pl line 40'. I think the variables are not passed into '@data' in the right order.

Can anyone tell me how I can fetch the data into the variable '@data' as required by the 'GD::Graph::lines'-module?

Thnx in advance...