Cross-fold validation done on whole dataset or training set?
Rather than a train-test split, I would recommend n-fold cross-validation or, better yet, leave-one-out cross-validation.


  My question, is how do I evaluate my model if it appears that based on the train/since it seems like my data is getting different results based on the splitting. 


The high variance in your error estimates is a consequence of a very small dataset.  When sampling from such a small dataset, it's super easy to wind up with train and test splits that aren't representative.  Cross-validation will give you a more stable error estimate.


  What I've done is: run the entire scrip in a loop and iterate over 10 different splits and then plot the error bars on the ROC curve. Is this reasonable? 


It's a very good idea to run your model evaluation routine several times and average the results.  It sounds to me like you're manually running a less-controlled version of cross-validation.

I'm not sure what you mean when you say "plot the error bars on the ROC curve".  Is area-under-ROC your accuracy metric?  Or are you computing the accuracy then somehow plotting that on the same axes as an ROC curve?



This wasn't part of your question, but it may be helpful nonetheless.  When you have a dataset with more features than examples, then you are incredibly likely to run into problems related to the curse of dimensionality.  In the 302-dimensional space where your features reside, your dataset of just 77 examples is incredibly sparse.

You may want to consider simpler models (logistic regression, shallow decision trees, etc) and employ some type of regularization to discourage your model from learning spurious relationships.  You could also try to use a dimensionality reduction technique to eliminate some of your 302 features.