Timestamp and date datatypes not recognized in iReport

[memory721]

I've been writing reports in iReport and although I get the following error my report works fine in Jasperserver.

ORA_00932: inconsistent datatypes: expected TIMESTAMP WITH TIME ZONE got NUMBER.

However, I run into problems when I go back to the report and try to add or delete fields.  I am not able to do so. 

After speaking with jaspersoft support, I was told that the Timestamp_tz and date datatypes are not always recognized in iReport.  Is anybody else having this problem?  Does anybody have any solutions for this issue?

I would really like to be able to modify a report after it's been created without running into this error.

 

Thank you.