Php5 Application Segmentation Fault After Upgrade from 9.04 to 10.04, 10.10. or 11.10

Visiting the index of a legacy web application dumps core:

Program terminated with signal 11, Segmentation fault.
#0 php_apache_sapi_header_handler (sapi_header=0x7fc1379252f0, op=SAPI_HEADER_ADD, sapi_headers=0x7fc13549d000)
    at /build/buildd/php5-5.3.6/sapi/apache2handler/sapi_apache2.c:124
124 /build/buildd/php5-5.3.6/sapi/apache2handler/sapi_apache2.c: No such file or directory.
 in /build/buildd/php5-5.3.6/sapi/apache2handler/sapi_apache2.c
(gdb) bt
#0 php_apache_sapi_header_handler (sapi_header=0x7fc1379252f0, op=SAPI_HEADER_ADD, sapi_headers=0x7fc13549d000)
    at /build/buildd/php5-5.3.6/sapi/apache2handler/sapi_apache2.c:124
#1 0x00007fc132105280 in sapi_header_op (op=SAPI_HEADER_ADD, arg=0x7fc1325708c6) at /build/buildd/php5-5.3.6/main/SAPI.c:759
#2 0x00007fc132105898 in sapi_add_header_ex (header_line=0x7fc1379253b8 "Content-type: text/html", header_line_len=844564678,
    duplicate=0 '\000', replace=0 '\000') at /build/buildd/php5-5.3.6/main/SAPI.c:518
#3 0x00007fc132105929 in sapi_send_headers () at /build/buildd/php5-5.3.6/main/SAPI.c:799
#4 0x00007fc132099789 in php_header () at /build/buildd/php5-5.3.6/ext/standard/head.c:69
#5 0x00007fc13210db23 in php_ub_body_write (str=0x7fc1378e8230 "\027K\257:\333Rw6\027K\257:\333Rw6\220\216j7\301\177", str_length=0)
    at /build/buildd/php5-5.3.6/main/output.c:706
#6 0x00007fc13210e512 in php_end_ob_buffer (send_buffer=1 '\001', just_flush=0 '\000') at /build/buildd/php5-5.3.6/main/output.c:294
#7 0x00007fc13210eab9 in php_end_ob_buffers (send_buffer=240 '\360') at /build/buildd/php5-5.3.6/main/output.c:333
#8 0x00007fc1320fc325 in php_request_shutdown (dummy=0x7fc1379252f0) at /build/buildd/php5-5.3.6/main/main.c:1615
#9 0x00007fc1321e49d7 in php_handler (r=0x7fc1321e49d7) at /build/buildd/php5-5.3.6/sapi/apache2handler/sapi_apache2.c:526
#10 0x00007fc13620d228 in ap_run_handler (r=0x7fc1360130a0) at /build/buildd/apache2-2.2.20/server/config.c:159
#11 0x00007fc13620d69e in ap_invoke_handler (r=0x7fc1360130a0) at /build/buildd/apache2-2.2.20/server/config.c:377
#12 0x00007fc13621d210 in ap_process_request (r=0x7fc1360130a0) at /build/buildd/apache2-2.2.20/modules/http/http_request.c:282
#13 0x00007fc13621a088 in ap_process_http_connection (c=0x7fc136019290) at /build/buildd/apache2-2.2.20/modules/http/http_core.c:190
#14 0x00007fc136213cc8 in ap_run_process_connection (c=0x7fc136019290) at /build/buildd/apache2-2.2.20/server/connection.c:43
#15 0x00007fc136221db0 in child_main (child_num_arg=<optimized out>) at /build/buildd/apache2-2.2.20/server/mpm/prefork/prefork.c:667
#16 0x00007fc13622251a in make_child (slot=0, s=0x7fc1361b27f8) at /build/buildd/apache2-2.2.20/server/mpm/prefork/prefork.c:768
#17 make_child (s=0x7fc1361b27f8, slot=0) at /build/buildd/apache2-2.2.20/server/mpm/prefork/prefork.c:696
#18 0x00007fc1362225d7 in startup_children (number_to_start=5) at /build/buildd/apache2-2.2.20/server/mpm/prefork/prefork.c:786
#19 0x00007fc136222f54 in ap_mpm_run (_pconf=<optimized out>, plog=<optimized out>, s=<optimized out>)
    at /build/buildd/apache2-2.2.20/server/mpm/prefork/prefork.c:1007
#20 0x00007fc1361f83ca in main (argc=3, argv=0x7fffbd76d3f8) at /build/buildd/apache2-2.2.20/server/main.c:741

The following PHP modules are installed:

ls -l /usr/lib/php5/20090626/
-rw-r--r-- 1 root root 420448 2011-05-30 21:17 imagick.so
-rw-r--r-- 1 root root 39344 2011-10-13 23:21 pdo_pgsql.so
-rw-r--r-- 1 root root 100712 2011-10-13 23:21 pdo.so
-rw-r--r-- 1 root root 120896 2011-10-13 23:21 pgsql.so

cat /etc/lsb-release

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=11.10
DISTRIB_CODENAME=oneiric
DISTRIB_DESCRIPTION="Ubuntu 11.10"