madBasic is just a collection of basic freeware units. madBasic has nothing to do with exception handling.
What you're looking for is madExcept, not madBasic. madExcept internally uses madBasic, though. madExcept is available freely for non-commercial use. You can download the non-commercial version here:http://madshi.net/madCollection.exe
In terms of functionality, the non-commercial edition is identical to the commercial edition. The only differences are:
1) The non-commercial edition may not be used for commercial purpose, obviously.
2) The non-commercial edition doesn't ship with source code, while the commercial edition does.
3) The non-commercial edition's exception box has a "non-commercial" label in it, which when clicked on opens a browser page to www.madshi.net