Not enough information was provided for us to be able
to handle this bug. Please re-read the instructions at
http://bugs.php.net/how-to-report.php

If you can provide more information, feel free to add it
to this bug and change the status back to "Open".

Thank you for your interest in PHP.

Sample code:
-----
<?php
class bullshit implements iterator{
  function curent(){
  }
  function next(){
  }
  function current(){
    echo "current";
    throw new exception('bullshit');
  }
  function key(){
  
  }
  function rewind(){
  
  }
  function valid(){
    return (true); 
  }
  function __destruct(){
  echo "destructor";
  }
}
$f=new bullshit;
try{
  foreach($f as $thisF){
  
  }
}
catch (exception $e){
  echo "catch !!!";
}
?>
-----

Run results:

php test-zend.php
current
Fatal error: Couldn't execute method bullshit::key in Unknown on line 0
destructor
(shell returned 255)

----

 So, it's clean that this appearance is incorrect. I think this is result of the same  bug in Zend engine, that troubles described in first comment. Also first trouble is exists to: error is appears in unknown module at line zero.

Please try using this CVS snapshot:

  http://snaps.php.net/php5-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php5-win32-latest.zip

I can't reproduce it with both 5.0.x CVS and 5.1 CVS.

No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

I am having this same problem. The iterator was working and the error seems to have popped up out of nowhere. I am using version 5.0.4.
My CollectionIterator class looks like this:

class CollectionIterator implements Iterator {

  private $_collection;
  private $_currIndex = 0;
  private $_keys;
	
  function __construct( Collection $objCol ) {
    $this->_collection = $objCol;
    $this->_keys = $this->_collection->getKeys();
  }
	
  function rewind() {
    $this->_currIndex = 0;	
  }
	
  function valid() {  
    return $this->_currIndex < 
        $this->_collection->getLength();	
  }
	
  function key() {
    return $this->_keys[$this->_currIndex];	
  }
	
  function current() {
    return $this->_collection->getItem( 
       $this->_keys[$this->_currIndex] );	
  }
	
  function next() {
    $this->_currIndex++;	
  }
	
}

This is the error:
Fatal error: Couldn't execute method CollectionIterator::key in Unknown on line 0

The __construct(), rewind(), and current(), methods are all called without error leading up to the call of the key() method.