Larry, I have also tried this on a field named "CLAIM_". The AERROR is returning: *** Column not found: CLAIM_

I know the column exists, because I can use:
QueryString = 'SELECT * FROM SOURCE WHERE RECORD_NUMBER= 15300'
Results = SQLEXEC( handle, QueryString, 'TARGET')

and this code returns 1 record with one of the columns being named CLAIM_

The table I am pulling data from has several fields that end with an underscore which all give me the same headache.