I noticed only now this topic.
i've a solution when it doesn't allow to arrange friendly, it's first workaround i tried and i've an explanation about it.
If i send invites/try to arrange, in the field "rank range" there is a textbox with "max", but it's translated to every language (f.e. in Italian is "Massimo"). Probably it (the procedure) misses the field due to a wrong conversion and goes out of time.
everytime i arrange friendly i edited that field to a numeric one (f.e. 20000) and it works without problems.
Try the same... and this is a good idea to find the bug.