Perl: Warning: Setting Locale Failed. Centos 6.9

I am receiving the following error message on my Centos linux server for past 15 days.

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = "en_US.utf8",
        LC_ALL = "en_US.utf8",
        LC_TYPE = "en_US.utf8",
        LANG = "en_US.utf8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

I am a bioinformatician and whenever i run perl or an application based on perl like fastqc, bwa, and samtools it gives me this error and does not let the programs run.

I tried to troubleshoot suing following ways.

1. set the locale using

   export LANGUAGE=en_US.UTF-8 export LC_ALL=en_US.UTF-8 export LANG=en_US.UTF-8 export LC_TYPE=en_US.UTF-8

2. Reinstall glibc

yum reinstall glibc-common

3. sh -c "echo -e 'LANG=en_US.utf8\nLC_ALL=en_US.utf8' > /etc/default/locale"

This generated a locale file in /etc/default which I never had before.

4. localedef -i en_US -f UTF-8 en_US.UTF-8

localedef -i en_US -f UTF-8 en_US.UTF-8 localedef -v -c -i en_US -f UTF-8 en_US.UTF-8 localedef -c -i en_US -f UTF-8 en_US.UTF-8

5. yum update

My current centos version is 6.9

the gcc version is

gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-18)

glibc version is

ldd --version
ldd (GNU libc) 2.12
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.

If I run the above tools fastqc/bwa/samtools using root it runs fine but without superuser it gives errors.

I am unable to figure out how to resolve this issue. Your help will be appreciated.