For the life of me, I could not figure out why this one CSV file was not importing correctly into InDesign CS6. I could see the datasource in the Links panel but nothing showed up in the Data Merge panel.
Through trial and error, I figured it out.
In the CSV file, one of the column headers used the word table. It's what the client gave me, so I never thought much about it. Once I changed the word table to seating, the CSV imported properly into my InDesign file and all was right with the world.
One word, I couldn't believe it...
Hopefully this will save you from all the trouble I went through.