At the end of the import process, if there were any errors that prevented some of the data from importing, the Import-Export Error Report will be shown, with a row for each record that failed to import. If you close that report before printing it or determining that you have all of the information necessary to correct the remaining data, you can reopen the report by going to Reports > Other Reports > Browse and open C:\Program Files (x86)\Wasp Technologies\MobileAsset\Reports\Import-Export Error Report.rpt.
The data about the errors is overwritten with each new import, so the report will only be able to show the errors from the most recent import.
When correcting data to re-import, those records should be copied to a new file, rather than re-importing the same file. If you reimport the same file, all of the records that were previously successful will now produce a Duplicate Record error, which may hide any other records that are still in error after your first attempt to fix them.