Adam I don't think it's an ioncube issue, because if I turn it off I don't even get the oops page.
I'm letting whmcs support chase this first, it's their software and getting errors should be this hard. I'll send in a ticket if they punt.
I've been using whmcs for over 10yrs and never had these kind of issues with a move but we'll see.
I'm playing with upmind, but seems like it take 20 extra clicks to do many same things. Still going to give it a go.