[Plugin: NextGEN Gallery] Page not found “loadingAnimation.gif”

Hi,

today I checked my error-log and I saw several times this error:
“Page Not Found – http://arseniums.com/…/…/wp-includes/js/thickbox/loadingAnimation.gif”
I know the path to the gif is wrong, cause it has to be http://arseniums.com/wp-includes/js/thickbox/loadingAnimation.gif
Can someone tell me please, what’s going wrong?

Thx in advance for your help