Take two of MAME 0.124 is now available on the Latest Release page. This update supplants the previous release. If you downloaded a binary previously, you'll need to grab a new one. If you downloaded the sources, you can either grab a fresh copy or apply this patch to the ones you downloaded. You can identify the fixed one in that it reports version 0.124a if you run it with -help, or in the version.c file.
Apologies for the excitement today! :)