Try the following to resolve the issue.

1. Make sure that the extensions are correct. Address lines 1 - 3 should all have the same extension of 00. When importing the contact information make sure that the extension also begins with 00. (See image below.)

User-added image

2. Make sure that the Address and Contact information columns are together on the excel file. If the address information is separated by another field (ie: Birth date, Gender, Religion, etc.) it may cause the system to recognize these as two separate addresses.
1. Open the excel document.
2. Copy address information
3. Paste it directly in front of the Contact Information
4. Save and Close the export.
5. You may have to reload the file into your import parameters.
6. Check the file layout to ensure that the edited file is there.
7. Remap the fields.