generate digital waveform repeatly with "write dig chan-ext clk" example

[Teddy!]

Hi all.

I'm new about labview & daq.

I wanna generate same 8bit digital waveform repeatly using while loop with "write dig chan-ext clk" example.

Because I wanna get a part of digital waveform signal generated repeatly in real time,

but this example generates digital waveform only one time.

So I changed the example, but I've got error message. 

There are some pics about changed example  & error result.

how can i fix it?

Thanks in advance.