user #1 is "guest", user #2 will be the first "old" user. This is as expected.
Any deleted users left "gaps", so if you had say:
nora 21
nick 22
joe 23
john 24
IF you deleted at anytime 22 and 23, then from your import user 24 (who is the user after 21) will become user 22.
again, expected and intended behavior.
IT's odd that it's stopping like that, is your host by chance killing the apache process from your import? this could cause that, as the import can be semi hard on the server.