odbc_num_rows always returns -1

Hi Everyone, As the subject says. I'm using 4.0.6 on IIS/win2k to a MSSQL 2000 database. I wish to check if a query returns any values, so the code I have is nothing more than: $numRows = odbc_num_rows($result); print ("$numRows<br>"); if ($numRows <= 0) { print("Nothing to show"); } Have I missed something.. with the result always being -1, it causes me some problems.. :) Thanks Pete