Issue with AS-11 files

I have emailed you directly.
Basically we would like to get your file from you to take a look at.
I have emailed a secure FTP location for you to upload to us.

Hi Team,

I've been using the product for a while now and it has always been a valuable asset to my workflow. However I have hit a problem this time and as far as I can tell it is because I have been editing with AS-11 mxf files. Can you help?

I get the error:

Writing AAF file
Adding assets to AAF file
Adding essence for asset [DRRB332X_01] to AAF file
Opening audio extractor for portion 0 of asset [DRRB332X_01]
Failed to initialise audio extractor with default bit depth of 16
Failed to create QT movie

No AAF file has been generated.
X2Pro Audio Convert LE 3.0.13

As far as I can tell DRRB332X_01 is an XMF file which is within my FCPX library which is accessible for X2Pro. Is this a bug?

I look forward to hearing from you.

Leigh Emmerson