Issue with ForEach cmdlet

Working on a script with the code pasted below. I am getting a message"cmdlet ForEach-Object at command pipeline position 2 Supply values for the following parameters: Process[0]" If I enter a value the Process[x] repeats with a incremented value. If I respond with a null I receive a response that contains the import command and the script terminates. Can anyone tell me that the initial message means?

    Import-Csv $InFile | ForEach
            {
            $FirstName = $_.FirstName; $LastName = $_.LastName;    $DisplayName = $_.DisplayName;    $Upn = $_.UserName;    $UPassword = $_.Password
            $CheckMailbox = $null; $CheckMailUser = $null
            # %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
            #            Check to see if the user account exist.
            #            If not then create it.
            # %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
            $CheckMailUser = Get-MsolUser -User $Upn
            If ($CheckMailUser -eq $null)
               {
              New-MsolUser -UserPrincipalName $Upn  -DisplayName $DisplayName -FirstName $FirstName -LastName $LastName -UsageLocation $Location -LicenseAssignment $LicenseAgreement -Password $UPassword -StrongPasswordRequired $False
              "$UPN - User account added" | Out-File $LogFile -Append
             }
            Else
               {
                   "$UPN - User account exist" | Out-File $LogFile -Append
               }
        }