Virtual machine hangs when trying to login after beeing idle for som time

Question

I'm using Microsoft Virtual PC 2007 to run a linux virtual machine, but after some time I can't login to it -- not from the instance on the localmachine or ssh in to the machine. Both give the same response. The login process doesn't finshf, the image shows where it stops:

This only happens when the vm has been running for some days, if I reboot it works fine again for some time before it locks up like this again.

Does anyone have an idea of why this is happening?

Edit: Here are the files.

ls -l /var/pam.d/:

-rw-r--r--  1 root root 1208 2011-01-20 09:17 common-account
-rw-r--r--  1 root root 1260 2011-01-20 09:17 common-auth
-rw-r--r--  1 root root 1509 2011-01-20 09:17 common-password
-rw-r--r--  1 root root 1201 2011-01-20 09:17 common-session
-rw-r--r--  1 root root  182 2009-04-17 09:53 atd
-rw-r--r--  1 root root  384 2009-04-04 07:42 chfn
-rw-r--r--  1 root root  581 2009-04-04 07:42 chsh
-rw-r--r--  1 root root 3592 2009-04-04 07:42 login
-rw-r--r--  1 root root   92 2009-04-04 07:42 passwd
-rw-r--r--  1 root root 2305 2009-04-04 07:42 su
-rw-r--r--  1 root root   69 2009-03-27 17:18 samba
-rw-r--r--  1 root root  520 2009-03-21 10:28 other
-rw-r--r--  1 root root  168 2009-02-20 18:24 ppp
-rw-r--r--  1 root root  119 2009-02-17 04:22 sudo
-rw-r--r--  1 root root 1272 2009-01-28 21:58 sshd
-rw-r--r--  1 root root  289 2008-11-12 16:47 cron

/etc/pam-.d/login: (comments removed)

auth       optional   pam_faildelay.so  delay=3000000
auth       [success=ok ignore=ignore user_unknown=ignore default=die]  pam_securetty.so
auth       requisite  pam_nologin.so
session    required   pam_selinux.so close
session       required   pam_env.so readenv=1
session       required   pam_env.so readenv=1 envfile=/etc/default/locale

@include common-auth

auth       optional   pam_group.so
session    required   pam_limits.so
session    optional   pam_lastlog.so
session    optional   pam_motd.so
session    optional   pam_mail.so standard

@include common-account
@include common-session
@include common-password

session required pam_selinux.so open

/etc/pam.d/common-account:

account[success=1 new_authtok_reqd=done default=ignore]pam_unix.so 
accountrequisitepam_deny.so
accountrequiredpam_permit.so

/etc/pam.d/common-account: common-auth

auth[success=1 default=ignore]pam_unix.so nullok_secure
authrequisitepam_deny.so
authrequiredpam_permit.so
authoptionalpam_smbpass.so migrate

/etc/pam.d/common-auth session: session

session[default=1]pam_permit.so
sessionrequisitepam_deny.so
sessionrequiredpam_permit.so
sessionrequiredpam_unix.so 
sessionoptionalpam_ck_connector.so nox11

auth.log:

(15:36 is problably when I tryed to ssh to the vm, and I got the fault and did a reboot.)

Jun 30 14:17:01 us CRON[1435]: pam_unix(cron:session): session opened for user root by (uid=0)
Jun 30 14:17:01 us CRON[1435]: pam_unix(cron:session): session closed for user root
Jun 30 14:20:01 us CRON[1458]: pam_unix(cron:session): session opened for user root by (uid=0)
Jun 30 14:20:01 us CRON[1458]: pam_unix(cron:session): session closed for user root
Jul  4 15:36:35 us sshd[1945]: Server listening on 0.0.0.0 port 22.
Jul  4 15:36:35 us sshd[1945]: Server listening on :: port 22.
Jul  4 15:36:37 us sshd[1945]: Received signal 15; terminating.
Jul  4 15:36:37 us sshd[2052]: Server listening on 0.0.0.0 port 22.
Jul  4 15:36:37 us sshd[2052]: Server listening on :: port 22.
Jul  4 15:39:01 us CRON[2478]: pam_unix(cron:session): session opened for user root by (uid=0)
Jul  4 15:39:01 us CRON[2478]: pam_unix(cron:session): session closed for user root
Jul  4 15:40:02 us CRON[2565]: pam_unix(cron:session): session opened for user root by (uid=0)
Jul  4 15:40:08 us CRON[2565]: pam_unix(cron:session): session closed for user root
Jul  4 15:42:29 us login[2451]: pam_unix(login:session): session opened for user glennwiz by LOGIN(uid=0)
Jul  4 15:50:01 us CRON[2677]: pam_unix(cron:session): session opened for user root by (uid=0)
Jul  4 15:50:02 us CRON[2677]: pam_unix(cron:session): session closed for user root
Jul  4 16:00:01 us CRON[2754]: pam_unix(cron:session): session opened for user root by (uid=0)
Jul  4 16:00:01 us CRON[2756]: pam_unix(cron:session): session opened for user root by (uid=0)
Jul  4 16:00:02 us CRON[2756]: pam_unix(cron:session): session closed for user root
Jul  4 16:00:02 us CRON[2754]: pam_unix(cron:session): session closed for user root
Jul  4 16:03:37 us sshd[2799]: Accepted password for glennwiz from 148.140.26.150 port 51330 ssh2
Jul  4 16:03:37 us sshd[2799]: pam_unix(sshd:session): session opened for user glennwiz by (uid=0)