Please help fixing this Critical Error in implementation of SIFT algorithm

heyy.. i was trying to implement the SIFT algorithm which i got it from http://www.vlfeat.org/~vedaldi/assets/sift/versions/, this source code also included C-files.. and i also implemented MEX setup to execute the code in it.. so i started running the code from sift_demo... but it got stuck and gave the following error :

_*??? Attempt to execute SCRIPT siftlocalmax as a function: C:\MATLAB7\work\sift-0.9.0\siftlocalmax.m

Error in ==> sift at 248 idx = siftlocalmax( dogss.octave{o}, 0.8*thresh ) ;

Error in ==> sift_demo at 56 [frames1,descr1,gss1,dogss1] = sift( I1, 'Verbosity', 1 ) ;_*

could you please tell what kind of error is this and how can i get out of it.. looking forward for someones help!