About a month ago Adobe released CHF 3 for ColdFusion 8. I was excited about this release because it fixed a bug that has caused quite a few headaches I'm sure, that being application specific custom tags not working under load. At work we recently deployed the cumulative hot fix to one of our production clusters only to find we were still seeing the "Cannot find CFML template for custom tag" error on a pretty consistent basis. Determined to get the bottom of the issue, today I installed CF 8 locally (another post on this later) and put together a quick test app that I could run JMeter against. Our production servers run a few other hot fixes in addition to the CHF so I had a feeling that one of the other hot fixes may be causing the issue. Sure enough, as I tested each hot fix in combination with CHF 3 I found that application specific custom tag paths started failing under load with hf801-71643 applied. That particular hot fix attempts to address some of the issues with CFC serialization to AMF (Flash Remoting) in CF 8. There are numerous issues with CFC serialization to AMF in ColdFuison 8 and hf801-71643 does not fix all of them, so we opted to remove it in favor of working custom tag paths. Anyway, I just thought I'd share this in case others have installed CHF 3 only to find they are still getting "Cannot find CFML template for custom tag" errors with application specific custom tag paths. If your still seeing this error be sure be sure to check the other hot fixes you have installed as they may be the culprit.