Yes, it does appear to be the first 59,755 rows of data. The next row in the import file appears to be normal...no strange characters or duplicates.
EDIT: Further checking reveals that the next record did have a duplicates in the column that is the primary key. Thanks, Gary...back to step 1 to better cleanse the data source. This is what happens when you trust that another person did that! LOL
You may want to use the Data Profiling engine in TDP to identify other anomalies that may be present. e.g. the Profiler would have picked up straight away that you had duped keys, for example.