Errors and incorrect user info after applying BPMS 6.1.2 patch on Windows

Issue

After installing patch jboss-bpmsuite-6.1.2-patch over a clean install of BPM Suite 6.1, the UI shows the logged in user as ANONYMOUS with role NOBODY. After inspecting the server.log, it appears as if some classes are missing:

14:10:27,149 ERROR [stderr] (http-/0.0.0.0:8080-3) Caused by: java.lang.ClassNotFoundException: org.jboss.errai.marshalling.server.impl.ServerMarshallingFactoryImpl$Marshaller_for_org_jboss_errai_security_shared_api_identity_UserImplImpl from [Module "deployment.business-central.war:main" from Service Module Loader]

When I look in the backup folder of the patch folder, I see that in the original install the class was still in the /business-central.war/WEB-INF/classes/org/jboss/errai/marshalling/server/impl folder, after the patch it is missing. Probably along with other class files.

This is on a Windows 2008 R2P1 server machine. Other issues arise with file names being too long (according to Windows) when i move the patch folder or try to delete it.