You may get an error like this when trying to import an excel groundline file into the profiler:

The most common cause is an incorrectly named sheet. Name the sheet to groundline.
Note that this is the name of the sheet (tab) not the name of the file.

Another common problem is spurious information that may not even be visible. To avoid this problem create a new spreadsheet and copy only the data into it. This makes sure there is no data or formatting etc in any other cell that may give an error when importing.