I recently upgraded to MonoDevelop 2.2 Beta 2 (for the debugging capability, more on that later) on my Mac. When I opened a Moonlight solution and tried to run it, I got the following error: Could not find respack The project had lost its references to System.Windows and System.Windows.Browser. The cause turned out to be that when you upgrade MonoDevelop, it doesn't always update where it's pointing. The solution was to go to: /Library/Frameworks/Mono.fr... and delete all directories...
I recently did the upgrade to Snow Leopard on my MBP. To my dismay, Quicksilver no longer worked. It terminated immediately after launch. I found the the Beta 56a7 on here. I also had to remove Plugins.plist and the Plugins folder from ~/Library/Application Support/Quicksilver. I am ecstatic to report that Quicksilver is up and running again, and my Mac is happy