Well we need a lot more information in order to be able to help you.
Here are some things to check:
How are you locating your data? If coordinates, are they correct (correct signs, no zeroes, etc). If street addresses, again are they correct?
Do you have your location columns set correctly? For example are you accidentally importing street addresses as just zipcodes? (this would result in multiple pushpins appearing at the same locations - the zipcode centroids)
Which version of MapPoint are you using? Newer versions have more accurate road data
Does it tell you that it cannot locate the locations? Have a look at these locations.