problem in using mutt sending email
 

please want ask about mutt "i am new in linux still learning"
when i installed mutt in ubunto 10.10
and do sudo apt-get mutt
Package configuration

┌────────────────────────┤ Postfix Configuration ├────────────────────────┐
│ │
│ Please select the mail server configuration type that best meets your
│ needs.
│
│ No configuration:
│ Should be chosen to leave the current configuration unchanged.
│ Internet site:
│ Mail is sent and received directly using SMTP.
│ Internet with smarthost:
│ Mail is received directly using SMTP or by running a utility such
│ as fetchmail. Outgoing mail is sent using a smarthost.
│ Satellite system:
│ All mail is sent to another machine, called a 'smarthost', for
│ delivery.
│ Local only:
│
│ <Ok>
│ │
└─────────────────────────────────────────────────────────────────────────┘


that what get????
when in terminal use the commend of mutt
he told that must install sudo apt-get mutt
that i found

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
postfix
Suggested packages:
urlview mixmaster procmail postfix-mysql postfix-pgsql postfix-ldap
postfix-pcre sasl2-bin resolvconf postfix-cdb
Recommended packages:
default-mta mail-transport-agent
The following NEW packages will be installed
mutt postfix
0 upgraded, 2 newly installed, 0 to remove and 12 not upgraded.
E: Could not get lock /var/cache/apt/archives/lock - open (11: Resource temporarily unavailable)
E: Unable to lock directory /var/cache/apt/archives/




i don't know what must do ?

thanks

no answer??????