Fog error

Hello,
I am using Opsview4.5 built on Nagios Core 4.0.20130912. My ruby version is 2.2.

I have added some AWS hosts using default check_cloudwatch_status (first applied these: http://docs.opsview.com/doku.php?id=opsview4.5:opspacks:templates:amazoncloudwatch) script provided in Opsview and got following error:

/usr/local/nagios/libexec/check_cloudwatch_status:330:in `+’: no implicit conversion of NameError into String (TypeError)
from /usr/local/nagios/libexec/check_cloudwatch_status:330:in `rescue in ‘
from /usr/local/nagios/libexec/check_cloudwatch_status:321:in `’

Then I decided to upgrade to the latest version. The error message changed but Opsview still cannot run the check. It quits with following error:

/usr/local/rvm/rubies/ruby-2.2.0/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require’: cannot load such file — fog (LoadError)
from /usr/local/rvm/rubies/ruby-2.2.0/lib/ruby/site_ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require’
from /usr/local/nagios/libexec/check_cloudwatch_status:12:in `block in ‘
from /usr/local/nagios/libexec/check_cloudwatch_status:12:in `each’
from /usr/local/nagios/libexec/check_cloudwatch_status:12:in `’

I have previously installed fog using “gem install fog” command, however current ruby executable cannot “see” fog package (sorry, I am not familiar with ruby).

Here is a sample check command which returns errors above:
sudo -u nagios /usr/local/nagios/libexec/check_cloudwatch_status -a dpesmas01q.n11.local -i “i-XXXXaab1” -C CPUUtilization -f /usr/local/nagios/etc/aws_credentials.cfg

Can you please help?