ct_cmd_drop is usually only called when you close your connection (i.e. when the database handle is destroyed). The error message means that when ct_cmd_drop() was called there were still results pending, which usually points to an incorrect fetch loop in your code.

So I suggest that you take a look at your code and make sure that you process all the data that is returned by the server, or that you call ct_cancel() if you want to throw the remainder of the results away.

Michael