When you get this error, this is because there has been an issue with the processing of your input. Please check the following:
1. Does this error still occur if the column names are manually assigned on the submission page?
2. Are the basepair positions accidentally changed to scientific notation?
3. Are the columns consistently spaced by either a tab or whitespace?
4. Are there any rows with missing values?
5. Does the error still occur when I gzip my input file?
After trying the above and the issue still persists, you can open a thread on Google Users Group