roboticus is correct - a #tmp table is only visible from the session (connection) that created it.

You are either creating more than one connection explicitly, or DBD::Sybase is doing it for you because you attempt to start more than one query at the same time. If the latter you can find out more by setting the $dbh->{syb_no_child_con} attribute which inhibits the creation of child connections to handle multiple active statement handles.

Michael