Waveform file is empty?

For generating waveform, I did following steps:

a. Place an instance of "vsource" from "analogLib" in your schematic
b. Set the "source type" to "pwl"
c. Specify the path for csv or txt file in the properties form

d. In ADE->Setup->Simulation Files specify the Include Path to include the directory which contains the stimulus.txt file.

*.txt file:

0 1

0.5 1

1 0

In the log file, it shows a Error (CMI - 2197) : Waveform file 'tx.txt' is empty.

Any idea about this Error? I tried txt/csv/prn, but all failed.

Thanks,

Wood.