My ubuntu is 12.04LTS

I was used apt-get to install opera and cowsay. I've tried to execute them, but they all said

ubuntu@ubuntu:~$ cowsay

bash: /usr/games/cowsay: Permission denied

ubuntu@ubuntu:~$ opera-next

bash: /usr/bin/opera-next: Permission denied

I've already tried chmod a+x them but they won't work

Here is mount output

ubuntu@ubuntu:~$ mount

sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)

proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)

udev on /dev type devtmpfs (rw,relatime,size=1017476k,nr_inodes=214672,mode=755)

devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)

tmpfs on /run type tmpfs (rw,nosuid,relatime,size=410052k,mode=755)

/dev/sdb1 on /cdrom type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)

/dev/loop0 on /rofs type squashfs (ro,noatime)

/cow on / type overlayfs (rw,relatime,lowerdir=//filesystem.squashfs,upperdir=/cow)

none on /sys/fs/fuse/connections type fusectl (rw,relatime)

none on /sys/kernel/debug type debugfs (rw,relatime)

none on /sys/kernel/security type securityfs (rw,relatime)

tmpfs on /tmp type tmpfs (rw,nosuid,nodev,relatime)

none on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)

none on /run/shm type tmpfs (rw,nosuid,nodev,relatime)

/.filesystems/usr/usr.sqfs on /.filesystems/usr/squash type squashfs (ro,relatime)

aufs on /usr type aufs (rw,relatime,si=f8757c62)

binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,nosuid,nodev,noexec,relatime)

gvfs-fuse-daemon on /home/ubuntu/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,relatime,user_id=999,group_id=999)

gvfs-fuse-daemon on /root/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,relatime,user_id=0,group_id=0)

And ls -l of these 2 file

ubuntu@ubuntu:~$ ls -l /usr/games/cowsay

-rwxr-xr-x 1 root root 4421 Dec 22  2010 /usr/games/cowsay

ubuntu@ubuntu:~$ ls -l /usr/bin/opera-next

-rwxr-xr-x 1 root root 169 Jan 17 22:44 /usr/bin/opera-next

And cat of those file

http://pastebin.com/FP3MiQ6t (They are to long so I post them here)