gdb backtrace :

(gdb) bt
#0  0xb7d77218 in php_stream_url_wrap_http_ex (wrapper=0x81ea440,
    path=0xbfbbcbe4 "http://www.amazon.com/exec/obidos/tg/detail/-/0131867164/ref=pd_sbs_b_2/002-4279985-3370440?%5Fencoding=UTF8&v=glance", mode=0xb7e81808 "rb", options=4, opened_path=0x0, context=0x82341f4, redirect_max=19, header_init=0,
    __php_stream_call_depth=0, __zend_filename=0xb7eaed18 "/share2/php5.1-200512111530/ext/standard/http_fopen_wrapper.c",
    __zend_lineno=643, __zend_orig_filename=0x0, __zend_orig_lineno=0)
    at /share2/php5.1-200512111530/ext/standard/http_fopen_wrapper.c:648
#1  0xb7d77132 in php_stream_url_wrap_http_ex (wrapper=0x81ea440,
    path=0x823414c "http://www.amazon.com/exec/obidos/tg/detail/-/0131867164/ref=pd_sbs_b_2/002-9050535-1556846?%5Fencoding=UTF8&v=glance", mode=0xb7e81808 "rb", options=Variable "options" is not available.
) at /share2/php5.1-200512111530/ext/standard/http_fopen_wrapper.c:643
#2  0xb7d786f7 in php_stream_url_wrap_http (wrapper=0x81ea440,
    path=0x823414c "http://www.amazon.com/exec/obidos/tg/detail/-/0131867164/ref=pd_sbs_b_2/002-9050535-1556846?%5Fencoding=UTF8&v=glance", mode=0xb7e81808 "rb", options=4, opened_path=0x0, context=0x82341f4, __php_stream_call_depth=1,
    __zend_filename=0xb7eb478c "/share2/php5.1-200512111530/main/streams/streams.c", __zend_lineno=1773,
    __zend_orig_filename=0xb7ea77d4 "/share2/php5.1-200512111530/ext/standard/file.c", __zend_orig_lineno=701)
    at /share2/php5.1-200512111530/ext/standard/http_fopen_wrapper.c:703
#3  0xb7da9610 in _php_stream_open_wrapper_ex (
    path=0x823414c "http://www.amazon.com/exec/obidos/tg/detail/-/0131867164/ref=pd_sbs_b_2/002-9050535-1556846?%5Fencoding=UTF8&v=glance", mode=0xb7e81808 "rb", options=4, opened_path=0x0, context=0x82341f4, __php_stream_call_depth=0,
    __zend_filename=0xb7ea77d4 "/share2/php5.1-200512111530/ext/standard/file.c", __zend_lineno=701, __zend_orig_filename=Variable "__zend_orig_filename" is not available.
)
    at /share2/php5.1-200512111530/main/streams/streams.c:1771
#4  0xb7d2be29 in zif_file (ht=1, return_value=0x823b824, return_value_ptr=0x0, this_ptr=0x0, return_value_used=1)
    at /share2/php5.1-200512111530/ext/standard/file.c:701
#5  0xb7dfeba6 in zend_do_fcall_common_helper_SPEC (execute_data=0xbfbbd740)
    at /share2/php5.1-200512111530/Zend/zend_vm_execute.h:192
#6  0xb7dfe1a1 in execute (op_array=0x8233f2c) at /share2/php5.1-200512111530/Zend/zend_vm_execute.h:92
#7  0xb7ddc205 in zend_execute_scripts (type=8, retval=Variable "retval" is not available.
) at /share2/php5.1-200512111530/Zend/zend.c:1101
#8  0xb7d9386b in php_execute_script (primary_file=0xbfbbfa84) at /share2/php5.1-200512111530/main/main.c:1720
#9  0xb7e7f153 in php_handler (r=0x8219200) at /share2/php5.1-200512111530/sapi/apache2handler/sapi_apache2.c:584
#10 0x08076c6c in ap_run_handler ()
#11 0x080795f0 in ap_invoke_handler ()
#12 0x080997de in ap_process_request ()
#13 0x080961cf in ap_process_http_connection ()
#14 0x0807dedb in ap_run_process_connection ()
#15 0x0807e257 in ap_process_connection ()
#16 0x080b64f5 in child_main ()
#17 0x080b6814 in make_child ()
---Type <return> to continue, or q <return> to quit---
#18 0x080b6f7e in ap_mpm_run ()
#19 0x080624df in main ()
(gdb)

Verified and assigned to the streams mastah.

Ilia, it's your patch http://cvs.php.net/viewcvs.cgi/php-src/ext/standard/http_fopen_wrapper.c?r1=1.102&r2=1.103&diff_format=u causing it.

The following fix did the trick: 
http://tony2001.phpclub.net/dev/tmp/bug35629.diff

This bug has been fixed in CVS.

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.