unable to upgrade the application

guys,

I'm using the UntangleServer Build: 9.3.2, recently, it told me that there are some applications that I need to upgrade, such as "Brand Width" etc. I strictly follow the instructions shown at http://wiki.untangle.com/index.php/Upgrades , but it always shows me the exception:

An exception has occurred:

com.untangle.uvm.toolbox.PackageException
Captive Portal has been replaced with a new implementation in v9.4 and later.
The old Captive Portal in 9.3 can not be upgraded and must be removed from the rack before the system can be upgraded.

Error at http://192.168.0.1/jsonrpc/jsonrpc.j...1623659:461:37

anybody know why this happened? how should i do?

Thanks,
Johnny