++roboticus' solution should fix your immediate problem. You might consider a here document as a more readable alternative.

    my $xml = << "END_OF_XML";
<TEST testID="$count">
    <InputFile CopyFile="true" DeleteLocalFile="true">$_</InputFile>
    <PlaybackActions>
        <Start>
            <DumpTopology></DumpTopology>
        </Start>
        <MonitorPipeline>
            <Duration>-1</Duration>
        </MonitorPipeline>
        <Close>
        </Close>
    </PlaybackActions>
</TEST>
END_OF_XML

    print $xml;
[download]