An error occurred converting Final Cut XML to AAF

Glad that the media locations suggestion worked for you.
On the Main X2Pro page under "Help" and "Knowledge Base" there is an article or details about why the Media Locations in X2Pro are an important part of the App setup.

Here is a link to that page.
http://http://www.x2pro.net/sandboxing.html

We have seen this problem before especially with RED files.
Here is a little explanation for why the files had the problem that they did.

RED files are only allowed to reach a maximum of 4GB each. Therefore, when a larger RED clip is used or created, you end up with a set of files like this for 9GB of media:

CLIP.RMD (this is a very small metadata file)
CLIP_001.R3D (4GB)
CLIP_002.R3D (4GB)
CLIP_003.R3D (1GB)

In the FCP XML, there will only be a reference to the CLIP_001.R3D file, and when you try and read the audio samples from that file, the RED SDK knows that when the first file is exhausted, to start reading from the second. Unfortunately, because only the first clip is referenced in the XML file, only the first clip has a bookmark associated with it. This means that Apple’s sandboxing prevents access to the second file.

As X2Pro’s suggestion indicates, the way to get around this is to add the location of the RED files to the Media Locations in X2Pro’s Preferences.

Again, I am glad you got things working.

Media locations!
This was my first time using the app in a year and I didn't realize I had to root around in the settings to make it work. I set the media location and it worked perfectly.
Thanks.

Brian,

Would you please take a screen capture of your X2Pro Media Locations setup in the X2Pro Preferences?
After I see that, I should be able to explain what is happening here.

Many thanks.

A common problem?
I'm running OS X El Capitan 10.11.1 and this is the error message:

Writing AAF file
Adding assets to AAF file
Adding essence for asset [A003_C003_1003DA] to AAF file
Adding essence data to AAF file for portion 0 of asset [A003_C003_1003DA]
Reading audio data from audio extractor : 699050 samples
Failed to read 699050 samples
Error Requested 699050 samples from RED file but got 336930

Suggestion: If this RED file is spanned then ensure that an entry for the containing folder
has been added to the Media Locations in the Preferences.

No AAF file has been generated.
X2Pro Audio Convert LE 3.0.5