Ошибка, в то время как установка tomcat7

я - Тринг для установки tomcat7 на человечности 14.04 с помощью

$sudo apt-get install tomcat7 но это дает ошибку как

The following NEW packages will be installed:
  tomcat7
0 upgraded, 1 newly installed, 0 to remove and 555 not upgraded.
Need to get 0 B/35.6 kB of archives.
After this operation, 374 kB of additional disk space will be used.
Preconfiguring packages ...
Selecting previously unselected package tomcat7.
(Reading database ... 221751 files and directories currently installed.)
Preparing to unpack .../tomcat7_7.0.52-1ubuntu0.3_all.deb ...
Unpacking tomcat7 (7.0.52-1ubuntu0.3) ...
Processing triggers for ureadahead (0.100.0-16) ...
Setting up tomcat7 (7.0.52-1ubuntu0.3) ...
chmod: cannot access ‘/etc/tomcat7/tomcat-users.xml’: No such file or directory
dpkg: error processing package tomcat7 (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 tomcat7
E: Sub-process /usr/bin/dpkg returned an error code (1)

исправьте меня, если я делаю что-то не так?