issues regarding nineoldandroids-2.4.0.jar library

[engr-erum]

i already have used slidingpanel layout library in my project which has nineoldandroids-2.4.0.jar now once i m trying to use ViewHelpLib.jar then my project is not running and getting error

Unable to execute dex: Multiple dex files define Lcom/nineoldandroids/animation/Animator$AnimatorListener; [2015-07-07 14:17:49 - YouInApp] Conversion to Dalvik format failed: Unable to execute dex: Multiple dex files define Lcom/nineoldandroids/animation/Animator$AnimatorListener;

when i m not adding ViewHelperLib.jar then its giving me error at these lines //ViewHelper.setAlpha(cur, maxAlpha-0.5f_positionOffset); //ViewHelper.setAlpha(next, minAlpha+0.5f_positionOffset); //ViewHelper.setAlpha(prev, minAlpha+0.5f*positionOffset);

in adapter class the error is NPE ..... if i m commenting these lines then i m failed to achieve blur and higlighted effects on pagescroll ..... what steps i needed to take to overcome this situation ?