Thanks for your thoughts on this problem. I have noticed no regular pattern to the problem. Although I had nearly no failures at nights and weekends. However, the host talked about migrating my site(s) to a new server with less traffic. So his work might have improved things as well. I have no way of checking for load on the server. I am quite sure the load on my ap is very low; I suspect there are never as many as 3 users. Within this thread I got a couple of suggestions to give to the host to check his load. Shortly, I plan to insert the following code into the 3 most popular modules in the application, based on suggestions in the thread above:

warn `ls -l /proc/$$/fd/` . ' ';
[download]

However, if I were a hosting service, I would not allow commands like this to run; so I wonder if it will be blocked. If so, I will ask the host to run it; but that is not as useful, because one would like to run it right before my app crashes. Tony