Error retrieving newly captured image from a camera.

Question

Hello Everyone,
I am developing a user<->digital camera interaction application and I have a
problem with accessing newly captured picture. The thing is I am trying to save
the picture directly to the hard disk(this is possible with the camera I am using).
So normally, as stated in the camera PTP specification, the process can be described
in the following steps:
1). PTP command 'capture' - is send successfully to the camera( the camera captures).
2). Event 'RequestObjectTransfer' of ObjectHandle 0x12345678 - is received from the
camera and processed by my application.
3). GetObjectInfo (of ObjectHandle (0x12345678) ) command should be send to the camera.
4). ObjectInfo - received from the camera.
5). GetObject (of ObjectHandle (0x12345678) command send to camera.
6). Object of ObjectHandle (0x12345678) received from the camera.
7). Event TransferReady.
Everything works fine until I try to ask for the object's info:
- (CFDictionaryRef*) copyObjectPropertyDictionary
OSErr err;
ICACopyObjectPropertyDictionaryPB pb = {};
NSDictionary* dict;
pb.theDict = (CFDictionaryRef *)&dict;
pb.object = 0x12345678;
err = ICACopyObjectPropertyDictionary(&pb, NULL); //(**)
if (noErr != err)
NSLog(@"Error retrieving object info!");
else
return dict; // CFDictionaryRef *
return NULL;
The call (**) in the code above results in "err == -9905(kICAInvalidObjectErr)", so can
anybody tell me where my mistake is because there is obviously one (btw I
wrote the same application for Windows and the id 0x12345678 is recognized there.)

Answer 1

It is an OS X application, the GUI is already done(not all of the controlls are functional,
there are really a lot of them as the camera tend to be 'semi-professional' == 'a lot of
settings'). Actually, what my application can do at this point is read/write settings
from/to the camera, can 'sense' some event notifications, can capture image when the
camera is on external mode(no memory card) and the images are processed to the
'Current User'/Pitures folder and finally can look pretty sexy
The method that gave me headaches for a week or so was the common ICADownloaFile
it was not recognized by this particular camera as was not the 'copyObjectPropertyDictionary'
posted above. Instead I wrote two PTPPassThrough methods which are now accepted by the
Cam.