I hate to be one to blame bugs in the system, but in this case it looks like it might be a bug in DBD::Sybase because I tried essentially the same code with DBD::Oracle and did not get an error like that. Make sure you have upgraded to the latest versions. Then try it using a named column as the index indstead of a number, just to better isolate the problem. If this doesn't fix it you might want to report the bug. (note that mpeppler is something of a regular here)

However, please also follow smokemachine's advice because otherwise once this error is dealt with you fill still find that you don't have any data being returned.