The reason for this error is that you have asked Pd to create an object which does not exist.

There can be several reasons for this error, and the most common one is spelling. Object names in PD must be spelled correctly, and they are case sensitive.

[Osc~] or [OSC~] will not create in place of [osc~], for example, nor will [osc] without the tilde.

Sometimes users accidentally combine the creation argument and the object name, such as [+1] instead of [+ 1].

New Pd users also often get confused between Objects and Messages, which are very different types of elements which can be placed in the patch from the "Put" Menu.

You can use the "Find last error" function under the "Find" menu to track down which objects did not create.

this FAQ was originally published under the GPL at Pd's FLOSSmanual