I do not see that Premiere Elements 9.0/9.0.1 or other supports files with the .mxf file extension.
The term codec represents video or audio compression. .mxt is not compression but a wrapper format for the compression.
What is the video and audo compression for this file?
I might suggest
a. converting your ".mxf" to H.264.mov
b. try renaming the file extension from .mxf to .mov, .mpg, or .avi
We will be watching for your progress.