Ugly validate error when float given to integer column

[jfy133]

Here: SPAAM-community/AncientMetagenomeDir@a2f4f3f

Produced the following error:

SPAAM-community/AncientMetagenomeDir#1087 (comment)

TL;DR: TypeError: Cannot cast array data from dtype('O') to dtype('int64') according to the rule 'safe'

The long ugly tracveback would be hard for a contributor to read and parse, and also the error doesn't say 'where' the error happens. This should be caught and an un understandable error message printed.