I have been heavily using this type of a setup for several years by email only, and the last 3 years with a Bug Tracking Software.
I must say, the bug tracking software has made my life so much more peaceful. Nothing is left, forgotten, or slips through the cracks. It's easy to find trends in errors, and remember "all the times" it happened.
Our setup is like this:
1) Coldfusion + Appropriate framework with error reporting - It doesn't matter what you use. I have used Fusebox extensively and am making the transition to ColdBox. Both are very capable, in addition to Mach-II, FW/1, Model-Glue, etc. The key part you have to find in them is their ability to catch "onError", usualy in the application CFC.
2) Custom OnError Script - Wherever an error occurs, you want to capture the maximum amount of information about that error and email it in. What we do is, when an error occurs, we log the user out with a message of "oops, log in again". Before logging them out, the application captures the error and emails it to Fogbugz. Along with it, at the top we include the CGI variables for the IP address, browser being used, etc. Over time you will find the things you need to add.
3) Routing in Fogbugz. A 2 user version of Fogbugz is free, and hosted online. There are two main ways to submit bugs. One is to email one in at a time. So if an error happens 2000 times, you get 2000 emails, and 2000 cases. Not always the best to link them together, etc. They have a feature called BugzScout, which is essentially an HTTP address that you do a form post to with cfform with all of the same information you would have put into the email. There's plenty of documentation on this and something I've always wanted to get around to. I had a scenario of 2000 emails for the first time happen a few weeks ago so I'll be switching over to this.
Hope that helps. Share what you ended up doing and why so we all can learn too!