If(defined $data->{articleResponse}->{NOTICE}->{COMMENT}->{LR}->{REJECT_INFO}){

If(defined $data->{articleResponse}->{NOTICE}->{COMMENT}->{LR}->{REJECT_INFO}->{ERROR_REJECT_CODE}){

$rejCTag = $data->{articleResponse}->{NOTICE}->{COMMENT}->{LR}->{REJECT_INFO}->{ERROR_REJECT_CODE};
}
If(defined $data->{articleResponse}->{NOTICE}->{COMMENT}->{LR}->{REJECT_INFO}->{REJECT_INFO_DESK}){

$rejDTag = $data->{articleResponse}->{NOTICE}->{COMMENT}->{LR}->{REJECT_INFO}->{REJECT_INFO_DESK};
}
}

Here is a link to for XML-Simple interface just an fyi.
http://search.cpan.org/dist/XML-Simple/lib/XML/Simple.pm


I've encounter syntax errors along the if statements, please let me know what should i do.

what you should do is ditch Perl for a real programming language like Ruby, Java, or C#

But as it is, the error sounds a lot like you have a typo somewhere in your code.