I noticed that my Red-Gate tools were loading the DevExpress binaries from the GAC and not from the application directory. Both assembly copies were version 220.127.116.11; I'm not sure if and why there is a difference internally between the DevExpress assemblies loaded in the GAC and those installed with Red-Gate products but once I removed the 18.104.22.168 assemblies from the GAC all of the applications in the Red-Gate suite that were having problems work perfectly.
Please note that this is by design as the .NET Framework will search the GAC for an assembly (By strong name and version) and if it located it will be used... if it isn't located in the GAC; the framework will begin probing (as defined at http://msdn2.microsoft.com/en-us/library/yx7xezcf.aspx
) and will locate the correct
assembly in the app or probing path.
I've never seen this cause a problem in the past as one would assume that two binaries with the same strong name and version should be identical... but I didn't dig any deeper.