No they don't usually have many items on the invoice, but the fact is that at least 2 customers solved this problem by getting an enabler key (even though they could print invoices and had no complaints about the key).
This is not the issue of upgrade SERP. But serverip.dat in this case contains the value: 192.168.88.12:1301, so this is local IP of the server with SERP.
Anyway I don't understand what do you me...