With the plugins I tried so far (Geolocation, PushPlugin) there's an error in CDVCommandQueue line 162:
objc_msgSend(obj, normalSelector, command);
Causes a EXC_BAD_ACCESS when calling the plugin command (getLocation, register etc...).
Works fine with the uncommented line:
[obj performSelector:normalSelector withObject:command];
But there's a warning about an unknown selector.