WPDB -class problems

Hi,

at the moment Im writing a plugin which needs database access.
I tried to use the wpdb-class and have already set $wpdb global.

Here’s the code:

<–snip–>
function foo() {
global $wpdb;
$wpdb->query(‘SELECT * FROM table’);
}
foo();
<–snap–>

This Error returns:
“Call to a member function query() on a non-object in[..]”

Thanks in advance.

.risehigher.