When we designed extended call routing and remote inquiry ten years ago, we never imagined this design to last a decade. The function to announce a date like “January 1st, 2004” was implemented using a fixed set of audio files. We shipped files for years 2000 to 2009. For SwyxWare v6.10 we added audio for 2010 to 2030, because 2010 was not that far in the future anymore.
Today we had to learn that this was not sufficient. The ECR script function loading and playing the date audio files fails for years greater than 2009. You can observe this using remote inquiry or if you have a custom ECR script using the “Say Date” block. Instead of the correct announcement you’ll get “invalid date”. It is rather embarrassing that we didn’t recognized this during v6.10 tests. 
For v6.12, v6.20 and SwyxWare v7.0 you will find a fix here:
http://www.swyx.com/support/ssdb.html?kbid=kb4081
(At the time of this writing the KB-Article is not live yet)
The fix is an updated template_v4.3.vbs file. If you’re still using an older SwyxWare version please contact you support channel for help.