It is possible that Text::xSV can point it out for you. The biggest likelyhood is an unmatched " causing it to read the entire rest of the file as one really, really long line. (It keeps switching from quoted to nonquoted and back as it hits ", and always hits the end of line inside quotes and includes the return in a field.)

If you post 3 lines from the file (before that line, on that line, and the next line) I should be able to visually spot it. But before you post, verify that DBD::CSV thinks that those 3 lines are only 2 rows.