SQL & PL/SQL

Hi gurus,
I have done the search on this forum for the ORA-24338 error (statement handle not executed) and found two threads, but none solved my particular problem. Here is my strange problem.

I have a stored procedure for many years now and it has been working like a charm until today. The procedure takes two input date params (start date and end date) and is used in a Sybase PowerBuilder datawindow. I get this ORA-24338 error if I use an end date of 01/31/2008, but no errors if I use an end of date of 01/30/2008, while using the start date of 01/01/2008. The other strange thing is any end date for Feburay 2008 will get this error. There is no problem when using 12/01/2007 to 12/31/2007, 01/1/2007 to 01/31/2007, 02/01/2007 to 02/28/2007.

I have tripled checked that I do have data for 1/31/2008 and every day for 2/2008. My last row date/time for 1/31/2008 is1/31/2008 23:34:12 and last row date/time for 2/29/2008 is 2/29/2008 23:39:12 （we are 24/7).

I have no idea why I get this error but guess we have some corrupted data? Could someone please help me figure this out?

Thank you very much!

Ben