beagled: System.Uri could not be loaded (mono 1.1.7-0ubuntu6)

When I upgraded mono 1.1.7-0ubuntu5 (I think) to mono 1.1.7-0ubuntu6, beagled stopped working

When I upgraded mono 1.1.7-0ubuntu5 (I think) to mono 1.1.7-0ubuntu6, beagled stopped working. I got a bunch of errors of the form:

** (/usr/lib/beagle/BeagleDaemon.exe:17536): WARNING **: The following assembly referenced from /usr/lib/beagle/BeagleDaemonLib.dll could not be loaded:
     Assembly: System (assemblyref_index=1)
     Version: 1.0.5000.0
     Public Key: b77a5c561934e089
The assembly was not found in the Global Assembly Cache, a path listed in the MONO_PATH environment variable, or in the location of the executing assembly (/usr/lib/beagle).

** (/usr/lib/beagle/BeagleDaemon.exe:17536): WARNING **: The class System.Uri could not be loaded, used in /usr/lib/beagle/BeagleDaemonLib.dll (token 0x01000066)

.....

** (/usr/lib/beagle/BeagleDaemon.exe:17536): WARNING **: The following assembly referenced from /usr/lib/beagle/Util.dll could not be loaded:
     Assembly: Mono.Posix (assemblyref_index=1)
     Version: 1.0.5000.0
     Public Key: 0738eb9f132ed756
The assembly was not found in the Global Assembly Cache, a path listed in the MONO_PATH environment variable, or in the location of the executing assembly (/usr/lib/beagle).

** (/usr/lib/beagle/BeagleDaemon.exe:17536): WARNING **: Missing method chmod in assembly /usr/lib/beagle/Util.dll, type Mono.Posix.Syscall