Your eval statement declares several lexical variables, but then you expect them to be available via the symbol table as globals! That won't work, just as the following won't work:

my $foo = "blah";
print $main::foo; ## whoops, not the same variable
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In addition, eval creates a fresh lexical scope, so the scope of the lexical variables is only within that eval. You can't get such a thing to work with lexicals + eval:

eval 'my $foo = 1';
print $foo; ## whoops, outside of $foo's scope
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It defeats one of the major purposes of lexical variables (that is, compile-time checking of variable bindings). You'll have to use either globals, or perhaps a hash of values if you want to instantiate variables via eval (and have them visible from outside the eval).