CSV use comma as separator and use double quotation as escape character. This means
1. If your data field contain separator or CR/LF, you must escape it with double quotation
Example: aaa,"b1,b2"
2. If your data field contain double quotation, you must use two double quotations (just like Text value in OutSystems )
Example: aaa,"b1,"",b2"
The error you mentioned means your data contains only one double quotation
Example: aaa,"b1,",b2"
So you'd better check your CSV file just after 55563 records.
Best Regards
Wei