I agree with moritz that you're not providing quite enough information for others to figure out what the problem is. However, I would suggest that you double check your XML file to ensure that it is compliant XML.

If you look at the "Caveats" subsection under the "Description" of the documentation for XML::Simple, it explains some things that need to be done in order for XMLout to produce compliant XML that can be read back in with XMLin. Check to see if the "rules" mentioned there are being followed by your XML file.

Also, the "Error Handling" section mentions the need for the XML input to be compliant XML. You can try using the eval block like the example given there to see if that will provide you with more details on problems with parsing the XML file.

If you're having problems trying to figure out the data structure of what was read in, I'd suggest that you try using something like Data::Dumper or Data::Show to help out.