You are not checking if the regex matched before you use the value of $1.

Changing the guts of your code to the following may give you the desired result.

    if( $line =~ /\s+<\w+\/?>(.*)<\/\w+>/ )
    {
        $line = $1;
        print "$line\n";
    }
    else
    {
        print "no match\n";
    }
[download]

Output:

First_Table
no match
[download]

Finally, why did you comment out use strict, and if you're parsing what appears to be XML or HTML, why not use a parser?