Cause
The cause of this problem has been identified in Bug 7018855. It is caused by the loading of the dtd via http while validating the document while Parsing a manifested DOM.

Solution
-- To implement the solution, please execute the following steps:
Switch off dtd validation, then the procedure runs to completion in 10.2.0.3, 10.2.0.4 and 11.1.0.6
Workaround
SQL> alter session set events ='31156 trace name context forever, level 2';