The problem was on the agent host; there’s an environment variable, COMPLUS_Version, set to v4. This forces FLDNSvc.exe, and in turn CatalystAgent, to run under CLR 4.0 instead of CLR 2.0 that it was built for. The config file attached overrides the variable, making the FLDNSvc.exe run under 2.0 again. This is preferable to the CatalystAgent.dll fix, because we don’t know what else can go wrong when it’s running under 4.0.
Extract file from FLDNSvc.exe.config.zip and place the config file in the same location as your FLDNSvr.exe.
Restart your applications