I have downloaded your data file, and went like
Name Size Bytes Class Attributes
a 65536x1 524288 double
y 256x256 524288 double
and everything is just fine to me. So, the only possible error is that: you have another file with a name (fname.txt) in your directory which is not the same file you uploaded (1372387722318.txt). Check this out and I'm pretty sure you'll have it working.