Basically, $data is intepreted as a string, and $attempt1 as a regex, so if you have special regex characters, they will never match up, no matter how you escape them.

To make a regex treat $attempt1 as a string, use \Q and \E:

$data =~ s/\Q$attempt1\E/$newstr/
[download]

man perlre for more info.

Updated: Added rant, as per tye :)