Data Sets in Photoshop CS2

I'm trying to learn about scripting in Photoshop CS2. By starting, I just want to import variable data into Photoshop, following the help instructions, however am having heaps of issues.

I'm using the Image > Variables > Data Sets > Import option.

My data looks like this..

Variable1
Ben
David
James
Mark

but when I try to import the text file, I get this error message...

"Could not parse the file contents as a data set. There were too many variable names in the first line of the text file."

Can anyone please tell me what I'm doing wrong?

Thanks