search and replace using reg expression

[Manjini]

I would like to search and replace an xml file with the ini content, but i am getting incorrect answer in my bb.xml with the same regular expression syntax without replacement.

My ini file
-----------
myPara para
lPara last_para
<mySeca>([0-9]+). <sec id=\"$1\">

My XML file.
-----------

<myPara>dsa fhasdjkh fjaksdhkjfh asjkdhfjk lashdkjfh ajksdhf jkasdhfjka sd</myPara>
<lPara>asdfh asgdhfgsdf asdhf asdhgf asd</lPara>
<mySeca>1. asdfgashdgfhasdghfg sdhfg asd</mySeca>

my perl part
--------------

$filename = "c:\\temp\\temp\\F&R.ini";
my $raw="c:\\temp\\temp\\aa.xml";
my $output="c:\\temp\\temp\\bb.xml";
open ($FIN,$raw) or die "Could not read from $raw, program halting.";
my $instr;
while (my $lines=<$FIN>)
{
	$instr.=$lines."";
}
open(FILE, $filename) or die "Could not read from $filename, program halting.";
$count = 1;
while (<FILE>)
{
chomp($_);
my($find,$replace)=split(/\t/,$_,2);
$instr=~s/$find/sub{$replace}->()/gei;
count++;
}
open(FOUT,">$output"); print FOUT $instr; close FOUT;

output bb.xml
------------

<para>dsa fhasdjkh fjaksdhkjfh asjkdhfjk lashdkjfh ajksdhf jkasdhfjka sd</para>
<last_para>asdfh asgdhfgsdf asdhf asdhgf asd</last_para>
<sec id=\"$1\">asdfgashdgfhasdghfg sdhfg asd</mySeca>

Can anyone help me to solve this