When I move the pivot point or the origin point of the thief into center it starts working well. But otherwise it keeps on running back and forth. Will there be a problem If I move origin point of all the enemies into center? 
That depends on what kind of calculations you do, some functions use the origin to work properly, and some will work better with center (depending on your desired usage case).
You should be able to position according to center also by adding this in any change position action:
X=DesiredPosition-ImageWidth/2
Y=DesiredPosition-ImageHeight/2
That should work because this is how we find image center (quick image in inkscape):
Image center X is = Origin point X + Width/2
Image center Y is = Origin point Y + Height/2
However, if you want to position an object without changing origin point, but you want the CENTER to be on those exact coordinates, you need to write as stated before:
X=DesiredPosition-ImageWidth/2
Y=DesiredPosition-ImageHeight/2
If I move the origin point to the centre, like from 0,0 to something like 24,24 , for all the enemies will it cause any problem? I am making platformer game. Like enemies have to chase and attack and jump.
I am not 100% sure as I don’t know if any functions require the origin point to be in the top-left corner, but you can definitely try and see. There’s a chance that things will work fine. If they don’t work fine, you can always set the point back to 0,0.
I mean file wont get corrupted
It should not corrupt the file if you change the origin point. If it did, that would be a bug, but I have not experienced any file corruption related to origin point.
Edit: To be safe, you can copy/paste your gdg file in windows to make a fast backup.
ok thank you!