Problem storing telephone numbers

Problem storing telephone numbers

Just trying to upload all my contacts.  Everything worked fine except for a number field (business number), which is set up the same as another number field (mobile number) with which I have no problems.

The business number field has imported all my data but left off the first character and removed a space between area code and the number.  When I try to edit the values I get this error message: -

java.lang.Long cannot be cast to java.lang.String

Anyone got any ideas what I'm doing wrong?  I've got the field set as 12 characters max, numbers.  Tried it with a text field instead and still no luck.

Thanks