GeorgeK - 4:17 pm on Aug 31, 2012 (gmt 0)
That's possibly a problem with your registrar's system, but it's not a *registry* issue, at least for .com.
What I've seen happen is that the registry will make the new expiry date be extended so that it's at exactly the 10-year mark (from the transfer date), and allow the transfer to go through.
So, for a domain name that was supposed to expire 9 years and 5 months from today, it won't expire 10 years and 5 months from today. It'll expire exactly 10 years from today, after the transfer (so one "loses" 5 months of time, but gets the domain at one's preferred registrar).