[ericbsmith]

I really need to add this one to the FAQ, because this is a known issue with an easy workaround: Load fewer data files when using _New Racial Template.

The error is caused when some of the trait lists used in the _New Racial Template get too big for GCA to handle; the trait lists get too big when too many data files are loaded (since more files make more traits available, with enough files loaded it eventually passes the threshold and "boom"). On an existing character you will also need to Resynchronize the Groups after loading the new Data Set and before using the _New Racial Template.