Unparseable Date in Schedule Trigger

Hello, we are using Oracle Business Intelligence 11.1.1.7.150120 on Linux 64-bit.

In one of our BI Publisher reports with Schedule Trigger, I had to add additional criteria/where-conditions and hence I modified the schedule trigger sql text, validated from SQL Developer by running it with appropriate parameters and the query runs fine.

Now, when I schedule the report with this schedule trigger selected, I see the following error for this job from the Job History page:

::FAILED_TO_EXECUTE_TRIGGER::[INSTANCE_ID=server.domain.com.1442425076323] [JOB_ID=36009]::

Unparseable date: ""::

java.text.ParseException: Unparseable date: ""

at java.text.DateFormat.parse(DateFormat.java:337)