KeyError: 8144 iterate through full data set - works on small set

Thanks for stopping by. I was hoping to get some help with an error. Here is my code:

a = ldamallet[bow_corpus_new[:751950]]

here is the error:

So if I check the length of the bow_corpus:

It is the right length. What is weird is that this code:

a = ldamallet[bow_corpus_new[:36000]]

runs just fine:

I just can't get it to iterate through the whole data set :( pls help

The data:

from KeyError: 8144 iterate through full data set - works on small set