Add hive after org.apache:
a = LOAD ‘nyse_stocks’ USING org.apache.hive.hcatalog.pig.HCatLoader();
b = FILTER a by stock_symbol == ‘IBM';
c = group b all;
d = foreach c generate AVG(b.stock_volume);
dump d;
Save–>execute and if it does not work follow, the steps in this blog post: http://idavit.blogspot.mx/2014/12/como-no-morir-en-el-intento-primer.html