Installing DB2 v10.5 on Windows 2012 R2

It's been documented elsewhere - but here is a trick to solving the "ValidatePanelCA failed" issue when attempting to install DB2 v10.5 to a Windows 2012 R2 server.

Error Message:
DEBUG: Error 2896:  Executing action ValidatePanelCA failed.

Solution:
Find another Operating System to create a response file for the install. I have a testing PC with 64-bit Windows 7 installed - so I ran the installer on that.

Here's a sample of my response file:
------------

PROD=DB2_SERVER_EDITION
INSTALL_OPTION=SINGLE_PARTITION
LIC_AGREEMENT=ACCEPT
FILE=D:\IBM\SQLLIB\
INSTALL_TYPE=TYPICAL

LANG=EN
DAS_CONTACT_LIST=LOCAL

INSTANCE=DB2
DB2.NAME=DB2
DEFAULT_INSTANCE=DB2
DB2.SVCENAME=db2c_DB2
DB2.DB2COMM=TCPIP
DB2_OLEDB_GUID=***
DB2_OLEDB_ADVANCED_PAGE_GUID=***
DB2_OLEDB_CONNECTION_PAGE_GUID=***
DB2_OLEDB_ENUMERATOR_GUID=***
DB2_OLEDB_ERROR_LOOKUP_GUID=***
DB2.PORT_NUMBER=50000
SSH_SERVER_INSTALL_DIR=D:\IBM\IBM SSH Server\
AUTOSTART_SSH_SERVER=NO
DB2.AUTOSTART=YES
DB2.USERNAME=db2admin
DB2.PASSWORD=***
ENCRYPTED=DB2.PASSWORD
DAS_USERNAME=db2admin
DAS_PASSWORD=***
ENCRYPTED=DAS_PASSWORD
CREATE_DAS=YES
DB2_EXTSECURITY=YES
DB2_USERSGROUP_NAME=DB2USERS
DB2_ADMINGROUP_NAME=DB2ADMNS
RSP_FILE_NAME=C:\install\PROD_SERVER.rsp
DB2_COPY_NAME=DB2COPY1
DEFAULT_COPY=YES
------------

I then copied the response file to my server - and ran this command:
setup -u PROD_SERVER.rsp -l db2setup.log

Install was then successful!

HOWEVER -- sometimes (for reasons I can't explain because the behaviour is not consistent) the Environment Variable 'DB2INSTANCE' does not get created so make sure you create it before the install :-)
variable: DB2INSTANCE
value: DB2

also make sure your db2admin user is created before the install and the password you give it matches the one you create in your response file!