Try having a conversation with Hal using the Test/Debug in the Hal Brain Editor. Run the "Ultra Hal Brain Editor" from Hal's menu or upir start menu and open up the brain you are using. Double click on "Test/Debug Script" and try having a conversation with Hal through this interface. If you get a blank response there you can expand the "Debug Information" tree and see exactly why it happened. You can right-click on the "Debug Information" and select "Copy Debug Info" and then paste the results here. That would help me out a lot to know why this is happening to you. The actual error might be caused by the sentence before the blank response, so keep an eye on the debug information during the conversation. Errors will be highlighted in red and the computer should beep.
