I'm having a similar problem adding support to an old site for docx.
In Include_Mimetype.php, in the BuildMimeArray function, when I set the MIME type for .docx to
application/vnd.openxmlformats-officedocument.wordprocessingml.document
I get an error message when uploading the file saying..."
application/octet-streamapplication/vnd.openxmlformats-officedocument.wordprocessingml.document
File Format not Allowed..."
Notice the octet-streamapplication in the error message which is not how I defined the MIME-type.
If I set the MIMEType like so...
application/octet-streamapplication/vnd.openxmlformats-officedocument.wordprocessingml.document
... the error message says...
application/octet-streamapplication/octet-streamapplication/vnd.openxmlformats-officedocument.wordprocessingml.document
Notice the octet stream-application twice.
I'm using CuteEditor 6.1.
Any ideas?
Mike Lockett
Software Architect
Laurie Anderson Design