References have to be dereferenced to print or iterate
through. Your code was attempting to access an element
of the list (array) instead of the entire array.

To access a single element of a referenced array you can:

print ${$entry->FTs->elements}[$number]

Make sure you use 'use strict' it would have thrown an
error when the example you gave was used, I am not
saying it would be any clearer as to how to solve it
but at least you would have a starting point :^)

For an array reference you would iterate as:

print "$_\n" for @{$entry->FTs->elements};

for a hash ref:

print "$_ = $hashref->{$_}\n" for keys %{$hashref};

See 'perldoc perlref' for more information.
or on the web at: perlref