Unfortunately, in my haste to release a fix for the crashes in Base 2.4, version 2.4.1 did not completely address the root of the problem. In order to limit the number of people downloading a broken release, I reverted back to 2.3.1 on this website and temporarily removed Base from sale on the Mac App Store.
Now, Base 2.4.2 is available for download from this website, and has been submitted to the Mac App Store for review. Once it has been reviewed, I will re-enable it for download. Once again, I apologise for the annoyance this has caused.