[dbutils] Strange exception - "String to date conversion error"

[Security Management]

I'm running the following query:
select weekday(date(mdy_proc(host_happened_date))) as day, count(*) as num
from alarm_history group by 1

The error is:
java.sql.SQLException: String to date conversion error Query: select
weekday(date(mdy_proc(host_happened_date))) as day, count(*) as num from
alarm_history group by 1 Parameters: []

Here is what it returns when I run it on the console:

[r...@sigma scripts]# selectit 'select
weekday(date(mdy_proc(host_happened_date))) as dow, count(*) as num from
alarm_history group by 1'
2 258.0
5 347.0
3 516.0
6 87.0
0 173.0
1 706.0
[r...@sigma scripts]#

What in the world does that error mean?

Thanks,
Mike.