Seems very odd, here's a couple of suggestions:
When you check the CSV file is there anything odd about the 11th or 12th record, a badly quoted string? a dangling apostrophe? a strange character?
Try importing the CSV file into OOo Calc (or similar) to check if there are any errors and if there aren't try exporting it to a new csv file and then try to import that in the kaddressbook.
Good luck