ERROR: Message 'folderName' not understood

Hello;
I have the following code

d = Dictionary.new;
d.add(\folders -> PathName(thisProcess.nowExecutingPath.dirname ++"/Users/sdcarr/Documents/SuperCollider/AUDIO/").entries);

(
for(0, d[\folders].size -1,
	{|i|
		d.add(d[\folders][i].folderName -> d[\folders][i].entries.collect({
			|sf|
			Buffer.read(s,sf.fullPath);
		});
		)});
)

d.entries.postln;

could someone understand why Supercollider returns the following error?

ERROR: Message 'folderName' not understood.
RECEIVER:
   nil
ARGS:
PATH: /Users/sdcarr/Documents/SuperCollider/jaxa.scd
CALL STACK:
	DoesNotUnderstandError:reportError
		arg this = <instance of DoesNotUnderstandError>
	Nil:handleError
		arg this = nil
		arg error = <instance of DoesNotUnderstandError>
	Thread:handleError
		arg this = <instance of Thread>
		arg error = <instance of DoesNotUnderstandError>
	Object:throw
		arg this = <instance of DoesNotUnderstandError>
	Object:doesNotUnderstand
		arg this = nil
		arg selector = 'folderName'
		arg args = [*0]
	< closed FunctionDef >
		arg i = 0
	Integer:for
		arg this = 0
		arg endval = -1
		arg function = <instance of Function>
		var i = 0
		var j = 0
		var stepval = -1
	Interpreter:interpretPrintCmdLine
		arg this = <instance of Interpreter>
		var res = nil
		var func = <instance of Function>
		var code = "(
for(0, d[\folders].size -1..."
		var doc = nil
		var ideClass = <instance of Meta_ScIDE>
	Process:interpretPrintCmdLine
		arg this = <instance of Main>
^^ ERROR: Message 'folderName' not understood.
RECEIVER: ni

Did you save your file first? thisProcess.nowExecutingPath…won’t work on unsaved files.