Passing date/time parameters from unix

[mb]

Hello,
I am trying to pass date and sometimes date/time parameters from unix to Cognos. Does anyone know what format this should be in?  I'm trying to pass in a simple date and I've tried MM/DD/YYYY, YYYY-Mon-DD, MM/DD/YY, and Mon DD, YYYY.  Nothing seems to work!  The report works if I run it manually from Cognos.  This should be very simple, I know, but I'm stuck and am hoping someone can help.  Here's the error I get:

Report search path is: /content/folder[@name='SDK_Testing']/report[@name='mb']

Report failed: common issues are incorrect report/folder names and incorrect authentication.

Report failed: SOAP Error exception message:

Exception in thread "main" java.lang.NullPointerException
        at Cognos8Exception.getSeverity(Cognos8Exception.java:48)
        at Cognos8Exception.toString(Cognos8Exception.java:116)
        at Cognos8Exception.convertToString(Cognos8Exception.java:140)
        at reportrunner.main(reportrunner.java:878)


Thank you in advance!  Marybeth :)