I have recently migrated from Windows to Ubuntu. My current locale shows below output :- cha@COMPUTER:~$ locale LANG=en_IN LANGUAGE=en_IN:en LC_CTYPE="en_IN" LC_NUMERIC="en_IN" LC_TIME="en_IN" LC_COLLATE="en_IN" LC_MONETARY="en_IN" LC_MESSAGES="en_IN" LC_PAPER="en_IN" LC_NAME="en_IN" LC_ADDRESS="en_IN" LC_TELEPHONE="en_IN" LC_MEASUREMENT="en_IN" LC_IDENTIFICATION="en_IN" LC_ALL= When I am trying to install CHMSee (or any other Application) using UBUNTU Software Center. I am getting below error. installArchives() failed: perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Selecting previously unselected package libchm1. (Reading database ... (Reading database ... 5% (Reading database ... 10% (Reading database ... 15% (Reading database ... 20% (Reading database ... 25% (Reading database ... 30% (Reading database ... 35% (Reading database ... 40% (Reading database ... 45% (Reading database ... 50% (Reading database ... 55% (Reading database ... 60% (Reading database ... 65% (Reading database ... 70% (Reading database ... 75% (Reading database ... 80% (Reading database ... 85% (Reading database ... 90% (Reading database ... 95% (Reading database ... 100% (Reading database ... 207053 files and directories currently installed.) Unpacking libchm1 (from .../libchm1_2%3a0.40a-1_i386.deb) ... Selecting previously unselected package libjavascriptcoregtk-1.0-0. Unpacking libjavascriptcoregtk-1.0-0 (from .../libjavascriptcoregtk-1.0-0_1.8.0-0ubuntu2_i386.deb) ... Selecting previously unselected package libwebkitgtk-1.0-common. Unpacking libwebkitgtk-1.0-common (from .../libwebkitgtk-1.0-common_1.8.0-0ubuntu2_all.deb) ... Selecting previously unselected package libwebkitgtk-1.0-0. Unpacking libwebkitgtk-1.0-0 (from .../libwebkitgtk-1.0-0_1.8.0-0ubuntu2_i386.deb) ... Selecting previously unselected package chmsee. Unpacking chmsee (from .../chmsee_1.3.0-2ubuntu2_i386.deb) ... Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for desktop-file-utils ... Processing triggers for gnome-menus ... Processing triggers for hicolor-icon-theme ... Processing triggers for man-db ... locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Setting up qmail (1.06-4) ... The hostname -f command returned: $1 Your system needs to have a fully qualified domain name (fqdn) in order to install the var-qmail packages. Installation aborted. dpkg: error processing qmail (--configure): subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of qmail-run: qmail-run depends on qmail (>= 1.06-2.1); however: Package qmail is not configured yet. dpkg: error processing qmail-run (--configure): dependency problems - leaving unconfigured Setting up libchm1 (2:0.40a-1) ... No apport report written because the error message indicates its a followup error from a previous failure. Setting up libjavascriptcoregtk-1.0-0 (1.8.0-0ubuntu2) ... Setting up libwebkitgtk-1.0-common (1.8.0-0ubuntu2) ... Setting up libwebkitgtk-1.0-0 (1.8.0-0ubuntu2) ... Setting up chmsee (1.3.0-2ubuntu2) ... Processing triggers for libc-bin ... ldconfig deferred processing now taking place Errors were encountered while processing: qmail qmail-run Error in function: SystemError: E:Sub-process /usr/bin/dpkg returned an error code (1) Setting up qmail (1.06-4) ... The hostname -f command returned: $1 Your system needs to have a fully qualified domain name (fqdn) in order to install the var-qmail packages. Installation aborted. dpkg: error processing qmail (--configure): subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of qmail-run: qmail-run depends on qmail (>= 1.06-2.1); however: Package qmail is not configured yet. dpkg: error processing qmail-run (--configure): dependency problems - leaving unconfigured Can someone please help me in resolving this issue. The elaboration would be most appreciated since I am very new to this. Thanks, Anshuman Chakraborty