My trainer works fine except for option 8, i enter my inventory and press this option then i check my inventory again, but it has no effect on my encumberance whatsoever.
The developers of this game included a gigantic list of console commands that let you cheat to your heart's content.
Try this command to change your encumbrance:
player.forceav carryweight 10000
To open the command console in-game, press the ~ key (usually in the top left corner of keyboard under ESC key and left of the 1/! key)
The value I placed in this command (10,000) should be quite enough to solve your issue, but if you feel it is too little or too much, you can change this value to any number you want