Exporting Access DB to SQL Server: unexpected EOF?
First, use tab delimited files unless you want to use -t to specify a different delimiter (such as a comma). By default it will accept the tab.

Next, unless you're exporting data with the -n flag, use -c to import the data.

Finally, based on your comments, it looks like there is a mis-match between the size of your table columns and the actual width of the data. That's why you're getting notified the data is being truncated. Match those two up and you'll be all set.

You can check out the MSDN page on bcp for more information on flags, etc.