I left the "additional jdbc" and additional connection" fields blank because (1) I didn't know what they meant/what to put in there, and (2) didn't think I had any. The prereg log file just says "wrong number of fields in the csv file for this entry", which is not terribly helpful. I also trimmed off the header row. Is that a problem?
For Oracle it's 16 fields (must have 15 commas) and for SQL Server it's 11 (must have 10 commas). You must put the commas at the end even if your not using the "additional jdbc" field. The header is there to help fill in the fields and should be able to run without it.