Suwen,
da gave a good reply to your question but a few corrections were not pointed out. First, on your hash definition:

my %CountryCode = { 
   'com','Comercial', 
   'uk','The United Kingdom',
}  # a hash of country name
[download]

he corrected it as:

my %CountryCode = (
   'com','Comercial',
   'uk','The United Kingdom'
);

# a hash of country names
[download]

Note two things: 1) da changed your {}'s to ()'s (squiggles to parens) when intializing the hash; and 2) you left off a semicolon at the end of the statement.

Another thing not mentioned is your snippet:

if ($Country == $key){ #get the key of country name
   $CountryName = $CountryCode($key); #assign the key value to a varia
+ble
}
[download]

You should use ($Country eq $key) and not ($Country == $key).
eq is used for text comparison, == for numeric. suaveant's comment about sqiggles instead of parens applies to the $CountryCode($key) portion which should read $CountryCode{$key}.