Error message when importing data into SQL (Import & Export Data Wizard)
Import it as a string and do a derived column to convert it to a float. Whatever rows fail conversion will be re-directed to the error output and you can at least see what the problem is.

Flat File connections fail completely when they encounter problems. It's generally more productive to bring them in as loosely as possible and adding structure inside SSIS.

You almost certainly don't want to be using floats anyway. Use 'numeric' once they're inside the package.