Sometimes when importing .lxo file it fails saying I need Modo 501.

Note: I have Modo 501 installed and the Mesh was built in this Modo version.

Error in console:

Modo couldn't convert the .lxo file to fbx file.
You need at least modo 501 to import .lxo files directly.
Modo log file (Temp/ModoLogFile.txt) contents:

-- modo Event Log -- Mon Mar 19 14:50:49 2012

System -------- Time -------------------- Type -- Message -------------------------------------
Log System Mon Mar 19 14:50:48 2012 Info Log system started
Scripts Mon Mar 19 14:50:49 2012 Info C:/Program Files (x86)/Unity/Editor/Data/Tools/ModoToUnity.py
Mon Mar 19 14:50:49 2012 Info Exception "command failed: Scene load was unsuccessful.
C:/Users/Christopher/Desktop/Modo/Flat/Assets/Models/TV stand.lxo (80000000)" on line: 47

Repro Steps:

1. Launch Unity 3.5.1
2. Create new project and Import attached asset
3. Observe error in console

Desired outcome: The files to be converted without any problems

Actual outcome: The importing fails claiming I should use Modo 501 at least but I do have modo 501 installed.

Please view attached screenshot.