>Are the lines in the file variable length?

Yes, it's a CSV file. Also, turned out few rows had CRLF inside the column (e.g. after I split the file into 80 separate files and then imported I was surprised to find I lost 14 lines). After re-loading that particular file again I still got 14 rows less. Then I split that file into 10 and then again into 10 the one containing less rows and finally found that in one place we had CRLF inside the column.

The other issue was that few rows had extra , inside the column (I found these rows and removed that text). This was why originally I was unable to load it directly.