Linux

First my OpenSuSE machine at work decides to have it, and now I discover the reason why my Kubuntu laptop has been having horrible intermittent DNS resolution problems.
The offending entry in both cases was on the 'hosts:' line and said something like 'mdns4_minimal [NOTFOUND=return]' part away along.
At work, this utterly screwed up any attempt to resolve '.local' DNS names, which just happens to be the recommended way MicroSoft Active Directory is used, so it had to go there.

Four easy steps to get the free Railo CFML engine up and running as a J2EE app and linked to a front end Apache.
We'll pretend your application lives in /parth/to/dir/above/web/root/webrootdir this is the DocumentRoot of your Apache and the root (default) context of Tomcat. 

1. Download Tomcat 6 from the nice folks at Apache and install it.
Configure a new Host entry in it's server.xml for your new Apache web root.

You should run, not walk, to the nearest Adobe Flash Player download page, and install version v9.0.124.

Note, this is not some small fry error about connecting to sockets, or cross-domain access like what was in the other recent update.
This is SkyNet vs. Alien for the bragging rights over control of your computer.
From Flash (and therefore Flex too).

Although the download page for ColdFusion lists several different Linux versions (SLES 9 and 10, for instance) if you end up at the actual support matrix for ColdFusion then only a limited sub set of that list is actually supported for 64-bit native (SLES 10.1 only for instance, not 9, and not any other version of 10).

After joining the contributor list for Flex last week, it appears that I have the pleasure of saying that the first external patch to open source flex was mine - making it easier to build Flex on Linux (#SDK-14810).

For reasons best known to themselves, Adobe do not ship the trial Data Visualisation components with the SDK download, so you have to extract them from the Windows download yourself.
Update Aug. '09:The DV components are now available on their own, with full source and no need for a Builder licence to remove watermarks.
If you need older versions though, you'll still need the below instructions.

First, install the Flex 3 SDK:

If you are playing around with the Linux version of Flex Builder, CFEclipse, or generally mucking about with your Eclipse, or need to upgrade to a new Eclipse version, you've no doubt been annoyed at the way this removes all your carefully installed plug-ins.
Fortunately there is a way to keep them across Eclipse re-installs.

All you need to do is create a few magic directories and one file: