A "Commands out of sync;" error

Hi,

I try to use mysqli through ADODB to connect to my MySQL (5.0.15)
database.

I try to execute such a part of code:
$date = $this->db->Execute("call get_date()")->FetchObj->value;

and whatever I try to execute later, I get a message:
string(24) "select [at] result as result"
string(52) "Commands out of sync; you can't run this command now"

But when I execute
$date = $this->db->Execute("select date from table")->FetchObj->value;
everything is ok.

I have recently re-installed my MySQL server - about which setting did
I forget?...