File descriptor leak in Mongrel server?

Excuse my ignorance for I'm a RoR newby.

We have a number of RoR applications running on a server with a cPanel installation. One of the clients sites went belly up with the error message: Errno::EMFILE Too many open files - socket(2)

Digging a bit I found that the mongrel server had a large number of sockets open and appears to be leaking them fairly frequently. The lsof looks like this

mongrel_r 11184 username 193u unix 0xda4fa480 637209350 socket mongrel_r 11184 username 194u unix 0xf685a680 637408911 socket mongrel_r 11184 username 195u unix 0xcc2ea3c0 637684747 socket

The application doesn't do anything explicitly with sockets. As far as I know the RoR installation is standard - from what I understand the hosting company support installed it and RoR is only semi-supported by cPanel so they're somewhat reluctant/lack the knowledge to be of much assistance?

I did google searches of every combination of ruby/rails/socket/leak/ cPanel/file descriptor/etc that I could think of and didn't find anything. I'm not exactly sure of what versions of ruby/rails/mongrel we have installed but didn't find anything about this being a known issue that had been fixed. I'd warrant a guess that we're not running the bleeding edge at any rate and are likely a few versions behind but again I'm not entirely sure how ruby is installed/managed under cPanel/ WHM.

Any ideas on where to look further or what the issue could be?