Error restarting Life cam VX-3000

Hi,

I have written an application to capture from UVC compliant cameras using Media foundation's SourceReader.

A part of the application closes down and releases the camera and then restarts it. Below are the code snippets desribing it:

Initialize Source reader:

hr = MFCreateSourceReaderFromMediaSource(_mSource,
					 _mAttributes,&_sourceReader);

Get a frame synchronously:

    hr = _sourceReader->ReadSample(MF_SOURCE_READER_FIRST_VIDEO_STREAM,
		0, // Not using MF_SOURCE_READER_CONTROLF_DRAIN flag because we are not going to Buffer samples&actStreamIndex,&actStreamFlags,&timeStamp,&mediaSample);

We now clear & release the camera:

    SafeRelease(&_sourceReader);
    SafeRelease(&_mSource);
    SafeRelease(&_mAttributes);
    SafeRelease(&_nativeMediaType);

    for (DWORD i = 0; i < _count; i++)
    {
        SafeRelease(&_mmDevices[i]);
    }

    CoTaskMemFree(_mmDevices);

I then re-initialize the camera with a different media type and  call ReadSample again.

This work flow works with most cameras, but, with lifecam VX-3000, the ReadSample call after re-initializing returns the following failed HRESULT : 0x80070004

HRESULT_FROM_WIN32(ERROR_TOO_MANY_OPEN_FILES): The system cannot open file.

Am I missing anything while releasing the device? Thanks in advance for any ideas/suggestions on this.

Anchit