We see this error most often when users attempt to scrub an Excel spreadsheet. Because Excel will allow any character to appear in the "column header" record of the list, it is possible for the creator of the list to include characters that Call List Scrubber cannot process. Call List Scrubber is designed to remove any invalid characters prior to trying to use the column headers as field names. Unfortunately, sometimes this produces duplicate field names and when it does Call List Scrubber cannot continue. It might also be that after removing the invalid characters, the remaining characters still produce and invalid field name. 

There are two ways to work around this problem:

1) Go back to the original call list and edit the column headers to be short (under 10 characters) and/or eliminate any invalid characters (such as * ,, &, ^, #, @, etc.). Then try to scrub the list again.

2) Re-scrub the list, and this time remove the checkmark from the 'Field Names are in Row 1' box as shown in the two screens below. When you do this, Call List Scrubber will automatically assign field names such as A, B, C, or D. You can still check the sample box to see what a particular field contains and the process should continue normally after that.