You seem to be wanting to check that an XML document is 'well formed'. Here's a Perl one-liner that will do that:

perl -MXML::Parser -e "XML::Parser->new( ErrorContext => 3 )->parsefil
+e(shift)" your_file.xml
[download]

If you were incorporating it into a larger script, then you'd want to wrap it in eval { ... } and check the contents of $@ afterwards.

One trap with using XML::Simple for well-formedness checks is that the SAX parser included in the latest release of XML::LibXML does not die on all parse errors.