Index: pam_yubico.c
===================================================================
--- pam_yubico.c   (revision 124)
+++ pam_yubico.c   (working copy)
@@ -397,7 +397,7 @@
     }
   if (debug)
     D (("done. [%s]", pam_strerror (pamh, retval)));
-  pam_set_data (pamh, "yubico_setcred_return", (void *) retval, NULL);
+  pam_set_data (pamh, "yubico_setcred_return", (void *) (uintptr_t)retval, NULL);
 
   return retval;
 }
@@ -406,7 +406,7 @@
 pam_sm_setcred (pam_handle_t * pamh, int flags, int argc, const char **argv)
 {
   int retval;
-  int auth_retval;
+  uintptr_t auth_retval;
 
   D (("called."));

1) OS Version: Debian GNU/Linux 5.0.0 _Lenny_ - Official amd64
2) Kernel Version: Linux Kernel version 2.6.26-1-amd64
3) OpenSSH Version: OpenSSH_5.1p1 Debian-5
4) Yubico PAM Version: pam_yubico-1.11
5) "/etc/pam.d/sshd":
# PAM configuration for the Secure Shell service
# Administrative Level

auth required pam_yubico.so authfile=/etc/yubikeyid id=16 debug

# Read environment variables from /etc/environment and
# /etc/security/pam_env.conf.
auth       required     pam_env.so # [1]
# In Debian 4.0 (etch), locale-related environment variables were moved to
# /etc/default/locale, so read that as well.
auth       required     pam_env.so envfile=/etc/default/locale

# Standard Un*x authentication.
@include common-auth

# Disallow non-root logins when /etc/nologin exists.
account    required     pam_nologin.so

# Uncomment and edit /etc/security/access.conf if you need to set complex
# access limits that are hard to express in sshd_config.
# account  required     pam_access.so

# Standard Un*x authorization.
@include common-account

# Standard Un*x session setup and teardown.
@include common-session

# Print the message of the day upon successful login.
session    optional     pam_motd.so # [1]

# Print the status of the user's mailbox upon successful login.
session    optional     pam_mail.so standard noenv # [1]

# Set up user limits from /etc/security/limits.conf.
session    required     pam_limits.so

# Set up SELinux capabilities (need modified pam)
# session  required     pam_selinux.so multiple

# Standard Un*x password updating.
@include common-password

6) "/etc/ssh/sshd_config" settings:

ChallengeResponseAuthentication no
PasswordAuthentication yes