Good Day

The error is most likely caused by an invalid character entered in the source company.  You will need to edit the import file in notepad and look for quotation marks.

Correct the invalid character and combine the two separate lines into one and reimport your file.

Regards. 

thanks. it worked. but I have checked the entry and there is nothing like  "Double quotes, or Single Quotes, or Comma"  used in the entry description or even in the entry details itself. 

You can't see it in the file, open the export file in a text editor and you will see a line that doesn't start with a 1 or a 2, the line above has the issue, remove spaces until it lines up correctly with 2 for detail lines as the first number on the line. 
It's a pain and usually it's where someone has copied text from say word into sage and that has hidden characters that you can't see, or commas in a description