can't pick up items sometimes ?

everytime a map drops i can't pick it up anyhelp

i think you would need screen shots or video of this phenomenon.

It could be that the items is landing somewhere out of reach (unlikely as it only seems to be maps)
Could be that you have some loot option on if you are partied up with others (for instance there is or was something about all map drops going to the map instance creator)
Or it could be that there is a lot of junk hidden and the stuff you do see is physically further away than the item name is shown on screen (occasionally has you either standing there (i guess off screen) or running towards it (edge of the screen)) but again, this seems unlikely as you claim it is only on map items.