Attempting import from csv file getting the following error message.

There was an error opening C:\Documents and Settings\Dave Cooley\Desktop\KR4X-4b.csv: `Tone ' is not in valid list: ['', 'Tone', 'TSQL', 'DTCS', 'DTCS-R', 'TSQL-R']

What is this error message telling me? I place it next to a csv file that WILL import and the fields all look identicle.