Problem with array and variables as index

[Free Rider]

Hi,
i have a problem determining a matrix value by using a variable as
index of the array.:
I'm using php 4.3.11 + win xp SP2 + apache 1.3.33
I wrote a class in which there is an array defined as follows. There is
also a method to get the value of a given element of the array.

class obj1 {
.....

foerach (...) {
$this->_rows[] = array($key=>$value);
}

function _foo ($key, $offset=0) {
....
return $this->_rows[$offset][$key];

}
......
}

Then, I have another class which contains an istance of obj1 and a kind
of wrapper to the _foo method:

class obj2 {
....
$this->obj =& new obj1;
....
function bar ($key, $offset=0) {
//eg. key='test' offset=0
echo $this->obj->_foo($key, $offset);

}
....
}

If I call the bar('test') method I get a NULL value, but if in the _foo
method i put echo $key.$offset it prints correctly 'test0'. Also, if I
put in _foo echo $this->_rows[0]['test'] it prints the correct value,
BUT if I echo $this->_rows[$offset][$key] it prints nothing!!
I can't understand where the problem is.... is it a bug?

Thanks for your answers!