In Pro Tools (LE) 6.4, the MIDI Controllers do not get installed when you install Pro Tools. Only the Command|8 MIDI controller will show up, if you have selected to install it when Pro Tools 6.4 was installed.
Here's how to manually install them from the Pro Tools v6.4 CD:
1) Close Pro Tools.
2) Put the Pro Tools 6.4 CD in the drive. Start Menu > My Computer > Double-click on the Pro Tools CD.
3) On the Pro Tools CD, Additional Files > Unsupported Software > Controllers.
4) Now, the MIDI Controller files on the CD can be manually installed onto the system hard drive. Select the MIDI Controller file that is needed to install into Pro Tools (ie. HUI). Edit Menu > Copy to Folder.
5) Use the Navigation window and go to: Local Disk (C:) > Program Files > Common Files > Digidesign > DAE > Controllers. Select the Controllers folder. Click on the "Copy" button. Now, the controller file you copy from the CD to the Controllers folder will show up in the Peripherals dialog box in Pro Tools.
6) In Pro Tools > Setup menu > MIDI Controllers Tab > Pull down menu should list the MIDI controller your copied from the Pro Tools CD.