One of the solutions tells:
Using a standard Tomcat installation and a
tomcat user with no login shell, attempts to start Tomcat failed with a "This account is currently not available." message. However, the tomcat user shouldn't have a shell available as it's not a login account. Updating the tomcat6 command in/etc/init.d/tomcat6 to specify the shell when invoking Tomcat fixes this.Some other solutions tell that account should be reset, password changed and shell set from nologin to bash. In all these cases you are making a security hole, tomcat account should be disabled in all cases. My suggestion would be to check if you had tomcat user defined before, for example when deploying tomcat6.. Then check if TOMCAT_HOME matches tomcat users home. If TOMCAT_HOME value is set to /usr/share/tomcat6 and you are starting tomcat7 - you will get the same error as with a locked account.
