Gem not found when I have just installed it - ruby

Question

I am creating a Ruby script which reads data from an Excel sheet and put its data on a MySQL database. I have written it and installed the necessary gems. However, when I try to run it via my cPanel host and I get the following error:
Array ( [0] => /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- ruby-mysql (LoadError) [1] => from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' [2] => from ../ruby/InsertarFaltantesExcel.rb:2 )
Ruby Code:
require 'rubygems'
require 'ruby-mysql'
require 'spreadsheet'
#load './spreadsheet.rb'
con = Mysql.connect('xx', 'xx', 'xx','xx')
ARGV = "--help" if ARGV.empty?
workbook = Spreadsheet.open(ARGV[0])
sheet = workbook.worksheet(0)
sheet.each do |row|
#faltantes = {
"id_verificador" => "#{row[0]}",
"order_id" => "#{row[1]}",
"id_proveedor" => "#{row[28]}",
"shipping" => "#{row[10]}",
"ean" => "#{row[4]}",
"isbn" => "#{row[5]}",
"description" => "#{row[8]}",
"sku" => "#{row[9]}",
"cost" => "#{row[40]}",
"order_price" => "#{row[14]}",
"master" => "#{row[39]}",
"quantity_purchased" => "#{row[11]}",
"total_price" => "#{row[12]}",
"condition" => "#{row[33]}",
"tracking" => "#{row[29]}"
}
insertar_faltantes(#faltantes, con)
end
def insertar_faltantes(hash, con)
statement - con.prepare("INSERT INTO articulos(art_id_verificador, art_id_orden, art_id_proveedor, art_shipping, art_N13, art_ISBN, art_titulo, art_SKU, art_cost, art_precio, art_master, art_cantidad, art_total, art_condition,
art_tracking) VALUES(?,?,?,?,?,?,?,?,?,?,?,?,?,?);")
statement.execute "#{hash['id_verificador']}", "#{hash['order_id']}", "#{hash['id_proveedor']}", "#{hash['shipping']}", "#{hash['ean']}", "#{hash['isbn']}", "#{hash['sku']}", "#{hash['cost']}", "#{hash['order_price']}","#{hash['master']}",
"#{hash['quantity_purchased']}", "#{hash['condition']}", "#{hash['tracking']}"
end

Answer 1

The gems in ~/ruby/gems/gems/ are not being recognised by your Ruby executable. Find where all the other gems are being kept and move these ones into there.
Alternatively, try using a different package manager. If you have installed gems successfully in the past, use the manager you used for that.