Does this happen with PHP 5.2.11 ? Does this happen using local filesystem instead of remote ftp site?

Does not happen with 5.2.11
Does not happen with local directory

ftp://...@localhost/php5.dll.001
fopen 2
fread
fwrite
ftp://...@localhost/php5.dll.002
fopen 3
fread
fwrite
ftp://...@localhost/php5.dll.003
fopen 3
fread
fwrite
ftp://...@localhost/php5.dll.004
fopen 3
fread
fwrite
ftp://...@localhost/php5.dll.005
fopen 3
fread
fwrite
done

New information

Reproduce code:
---------------
<?php
$file = 'ftp://your:self@localhost/test.txt';

echo "start\n";
$fo1 = fopen($file, 'rb');
echo "opened.1\n";
fclose($fo1);
echo "closed.1\n";
$fo2 = fopen($file, 'rb');
echo "opened.2\n";
fclose($fo2);
echo "closed.2\n";
?>


Expected result:
----------------
start
opened.1
closed.1
opened.2
closed.2


Actual result:
--------------
start
opened.1
closed.1


Same result if opening different files
Same result if opening different files from different servers

However, if I move first fclose() below second fopen(), it works as expected

The same problem can be reproduce with the following code 

<?php
$dir = 'ftp://your:self@localhost/';

opendir($dir);
opendir($dir);

This bug was introduce in 5.3 with the new way to manage references of stream context.

Patch can be found here (it modify the php_stream_context_set signature) :
http://www.adoy.net/php/stream-nofetch.diff

Or here (same version but with TSRMLS_FETCH to avoid any signature modification):
http://www.adoy.net/php/stream-fetch.diff

This bug has been fixed in SVN.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.

Thanks for the patch!

Did it make it in time for 5.3.1 ?
The opendir() test passes, but original issue remains

<?php
$file = 'ftp://ftp.gnu.org/gnu/m4/m4-1.4.13.tar.xz.sig';
var_dump(
 $fr1 = fopen($file, 'rb'),
 fclose($fr1),
 $fr2 = fopen($file, 'rb'),
 fclose($fr2)
);
?>

Unfortunately the patch was not applied on time for the 5.3.1 release and if I remember well, the opendir() test only crashed when PHP is compiled with --enable-debug. That's probably why you can't reproduce it.