Gif Animation "Echo" problem

Hello everyone and thanks for you help in advance.

I created this animation in premiere and exported it as a gif.

Originally the file had chroma key green background which i removed manually (frame by frame) in photoshop. When "save for web" -> save -> the output file suddenly has an "echo" shown in the animation (as if the older frame is not overwritten by the newer one).

Any suggestions how i can fix that?

Please not that i am still pretty much a bloody beginner in photoshop and the solution needs to be written in explaining it with a few steps so i have a chance to fix it :D

Thanks guys!

file: http://ift.tt/1DTzMFp