Here's a bug that's not documented on Macromedia's web site.
Error Occurred While Processing Request Error casting an object of type to an incompatible type. This usually indicates a programming error in Java, although it could also mean you have tried to use a foreign object in a different way than it was designed. The error occurred in /bla/bla/file.cfm: line 204 202 : <CFSET blurb="anything"> 203 : <CFSET encBlurb=URLEncodedFormat(blurb)> 204 : <CFSET decBlurb=URLDecode(encBlurb)>
That's right, URLDecode() blows up, for no good reason at all. Thanks to a Google search I figured out why. This happens if you select a column called URL and then try to use URLDecode() inside the query loop. Be aware: it doesn't matter if the URLDecode has anything to do with the URL column or not, mere proximity is enough to trigger the crash.
It doesn't work to qualify the name URL with the name of the query. I ended up making an alias for that column in my SQL so I could refer to it without using the dread word URL.