The IB website is working for me now, I just priced award seats from ORD to MAD in J. They're available and bookable on both the IB and BA websites, and they cost the same in Avios terms and taxes/fees. I set the country to Spain and the language to English for IB, if it makes any difference.

Incidentally, this may or may not be relevant. I needed a J award on AA from PHL to PHX a couple of weeks ago. BA only showed availability on AA1956 on 23 March, and no other flights were available that week on ba.com. Now all availability is gone on BA.com. AA.com still shows availability for PHL-PHX on most days, and specifically on all nonstop flights on 23 March. A J seat on AA1956 is currently available for 34.5K AA miles, which AA calls a "Web Special", with no changes once ticketed. All the other flights have J seats for 55K AA miles on that day. So clearly AA is offering some cheap award seats it calls web specials that are not being made available to oneworld partners. Could it be that the same is happening in the opposite direction?