The hutch is just going to smash down the carpet, as long as it's equally smashed it's not a factor. If you don't have padding under the carpet evenly, that might impact it a bit. Agreed that the carpet tack strips could be pushing it out of level a bit.
But also, are you using a level to really see what you're dealing with? The last thing you want to do is go through all the effort to level it and find that it was level to begin with. Yes, it's obvious, but sometimes that must be stated :)
I would check that the floor is level. Also, is the floor able to handle the weight of the piece in general? You could level all day long, if the floor is deflecting under it you're going to have problems (and by problems, I mean get the hutch out of there before it damages the structure, reinforce joists, etc to handle the weight and then put it back in).