1. Do you have more than 64 thousand rows? I think Excel 2003 has a limit of that.
--- I get this error even if the number of rows is as less as 10, It has something to do with the pl/sql developer not able to open the excel document.
2. Is the SQL really large? PL/SQL Developer puts the SQL statement into one cell on the second tab and there is a limit to how big it can be. I thought it gets truncated, but it might be something to look at.
-- I had tried "select * from tab;" I think this is a very small sql. I am guessing it has something to do with the compatibility between pl/sql developer and excel.
3. Perhaps one of the cell's data is throwing it off somehow. Can you open it if there is only 1 row? If so, you might be able to find the row that is causing the problem and report it. For example, see if the first half works. If so, check the second half. Keep dividing it until you have the row.
-- whenever I get this error, everytime I try doing it second time, and then it works perfect, If the reason could have been what you stated above, the problem would occur each and everytime. My problem is intermittent.