Has she tried porting there direct? If that's what's not working, has she tried going to the entrance itself in Apocrypha? If she doesn't have Necrom on her account, the only way to enter will be porting directly.

Have you tried grouping with her to see if that helps?

Most likely you mean Bastion Nymic, though your post title says "IA: Infinite Archive". There are different dungeons. To enter Bastion Nymic you have to get the quest in Necrom, then you have to collect five pieces of Daedric Ichor, which will be picked up by defeating Herald's Seekers, the zone's roaming World Bosses. After that you can enter.
(or let's say you get the Nymic daily, collect five ichors, group with your wife, who also has got the quest, then you both enter as a group)

Quest giver for the Infinite Archive is located inside the Archive, so you cannot get the quest without entering the instance.
And to re-enter archive grounds AFTER you run out of "threads" (lives) you have to reset the instance clicking the hourglass in IA hall
(though this implies she already could enter the IA, but spent all 3 or 4 treads granted from the start - this also contradicts your question).

Hope it does work out - let us know, 'kay?