When deploying code using Hibernate 3.1.1 libraries, we refer to the DTD at hibernate.org/dtd/hibernate-mapping-3.0.dtd in our mapping files. Whatever was changed at 14:25:39 overwrote a previously functioning version, affecting all of the code we were developing for the client.

Locally, we pointed to hibernate.sourceforge.net/hibernate-mapping-3.0.dtd which seems to resolve the issue.