Content-Type : text/xml #I have added this line in the perl web service like print "\nContent-type : text/xml\n\n" to check what exactly it returns.

if you have access to the service code, it would be trivial to crack. For example, start by finding out why the error message complains that it found an empty Content-Type but you print text/xml and your client sends text/xml; charset=utf-8