Silent install failure of ToadForDB2_Freeware_5.1.0.656 on Windows 8.1

I can run a regular install on Windows 8.1 just fine, but when I try to run a silent install it fails. I’m running the following command:

ToadForDB2_Freeware_5.1.0.656.exe /S /Lx “C:\temp\install.log”

the errors in the log are:

1: ERROR:DB2 Setup is unable to open the response file “”.
1: ERROR:Unable to set the response file “” in the up and running engine.
CustomAction DB2ConfigClientCA.2BC48F01_561E_4906_8321_946A9F5A90AA returned actual error code 1603 (note this may not be 100% accurate if translation happened inside sandbox)

Any ideas?

[View:~/cfs-file.ashx/__key/communityserver-discussions-components-files/18/install.log:550:0]

The 5.1 Freeware version of Toad for DB2 is not supported on Windows 8, and the silent install of 5.1 cannot be run with the exe installer on that OS.