You have several problems there. Your substitution string must be evaluated twice to get the $1 and $2 interpolated. Evaluation, however, does not like the regex style backwhack in $v2, and will simply take a bare dot to mean concatenation. Modify your code to something like this:

$text = 'Cheese.Bacon';
$v1 = qr/(\w+)\.(\w+)/;
$v2 = 'qq($2.$1)';
$text =~ s/$v1/$v2/ee;
[download]

I added use of qr() for $v1, but what you had was ok.

After Compline,
Zaxo