Flowcode Support Board

I want to turn on/blink 16 LED's, so I am using a bidirectional Multiplexer. The choice of which of 16 outputs is controlled by a 4 bit word sent to pins on the MUX. And an Enable which goes low, to send 5 V to the LED chosen. The results are not correct. I have hooked up a 4 X switch, to the MUX, and it works correctly. I am noting also, that the 2 second delay is > 2 sec.
Any ideas? Thanks in advance.