At 09:36 26/08/2010, Nick Ager wrote: To me, the intention of the original code has for sure not been to hide errors, but to provide a handy solution to capture unexpected errors. This method is the "heart" of the Pier's request interpreter ("eval"), and in that sense it seems well situated for processing those exceptions. Of course, there is room for fine tuning, but my understanding is that Pier has invested in avoiding such programming errors. Still, Pier is an extendable system and in that sense responsible for handling eventual errors in plug-ins. Error instead of MAError may be also explained in this way. No, programming errors don't, in general, make sense to end-users. Remedial measures could be taken if the error is related to end-user actions. For example, feeding unexpected content (not only by Pier, but also by its plug-ins). But in all cases, for end-users it seems better to have an application that keeps responsive, eventually with meaningful error messages, instead of a *wall back* window. Regards, Reza