Data Logging Ev3 2012 LabView

[Tony10]

Hi.

I'm attempting to record the difference between reflective light and a set value.  This is for a

a larger line following project using proportional control. Using the Data Viewer to access the file,

I receive, "Error in loading the file - Make sure your NXT is on and defragmented (NXT Terminal)" 

Attached in a screen shoot of the vi. and the error message.

I feel I'm making a obvious error, but I don't see it.  Can anyone help with this?

Thank.

Tony