Steps to Reproduce: 

    1) Get a DBus proxy to the ContactCapabilities interface
    1.5) Create an array of dictionaries of key type string and value type object
    2.) Add a new dictionary item to the array
    3.) Add ChannelType DBusTube, TargetHandleType Contact, and ServiceName whatever
    4.) Add another new dictionary item to the array
    5.) Add ChannelType StreamTube, TargetHandleType Contact, and ServiceName whatever2 (yes, I know ServiceName should be Service for StreamTube. This is what causes the crash)
    6.) Pass the array to ContactCapabilities.SetSelfCapabilities
   

Actual Results: What the application did after performing the above steps.

    telepathy-gabble crashes
    Error "Did not receive reply" can be seen in dbus-monitor output (obviously due to the gabble crash)

Expected Results: What the application should have done, were the bug not present.

    Issue an exception / ignore the erroronous item in the array, but do not crash gabble.

Build Date & Platform: Date and platform of the build in which you first encountered the bug.

    gabble 0.7.31 on Ubuntu 9.04 with Empathy 2.27.3