Error when adding 2 columns together

I created a Parquet table from a PSV file (onln_report_def.tbl) using these commands in Drill:

use dfs.tmp;

alter session set `store.format`='parquet';

create table onln_report_def2_PQ(
report_type_id,
platform_id,
combinedcapblt_id,
evt_type_id,
rslt_type_id,
category_id,
evt_multiplier,
success_multiplier,
failure_multiplier,
policy_multiplier,
evt_rslt_description)
as select columns[0], columns[1], columns[2], columns[3], columns[4],
columns[5], columns[6], columns[7], columns[8], columns[9], columns[10]
from dfs.`home/kathy/onln_report_def.tbl`;

Then I used this command to try to select a column called "SumOf2" containing the sum of report_type_id and platform_id:

select (report_type_id+platform_id) as SumOf2 from onln_report_def2_PQ;

This is the error that resulted:

Error: SYSTEM ERROR: org.apache.drill.exec.exception.SchemaChangeException: Failure while trying to materialize incoming schema. Errors:

Error in expression at index 1. Error: Missing function implementation: [castTINYINT(VARCHAR-OPTIONAL)]. Full expression: --UNKNOWN EXPRESSION-.
Error in expression at index 1. Error: Missing function implementation: [castTINYINT(VARCHAR-OPTIONAL)]. Full expression: --UNKNOWN EXPRESSION-..
Fragment 0:0

Thanks in advance.