When training, get "This column contains no data" message


I am retraining an extractor with a new URL and having issues with some of the data columns. For all columns, I am able to select the data on the page that I want. However, for some columns, this data does not appear in the floating data table, and it displays the message “This column contains no data”.

Also, for some of the columns where there is data displayed, rather than the data being displayed in the first 10 rows (there are 10 records I am training the extractor with), the first 10 rows are blank and the data is displayed in the 11-20th rows. When I run an extraction, this causes the data to be split into different rows - there is a block of 10 rows with data for 6 of the columns, then in the next 10 rows there is data for a different 4 columns.

Any help?