call of AudioSpec default

I just downloaded Unit-Lib and when Ulib.startup i get the following error message:

which refers to the fact that AudioSpec has no method called default.

ERROR: Message 'default' not understood.
RECEIVER:
Instance of AudioSpec { (0x118be18c8, gc=84, fmt=00, flg=00, set=02)
instance variables [1]
numChannels : nil
}
ARGS:
PATH: /Users/MacBook/Library/Application Support/SuperCollider/Extensions/Unit-Lib/UnitDefs/ringMod.scd

PROTECTED CALL STACK:
Meta_MethodError:new 0x11bbea6c0
arg this = DoesNotUnderstandError
arg what = nil
arg receiver = an AudioSpec(nil)
Meta_DoesNotUnderstandError:new 0x11bbec680
arg this = DoesNotUnderstandError
arg receiver = an AudioSpec(nil)
arg selector = default
arg args = [ ]
Object:doesNotUnderstand 0x1188fa6c0
arg this = an AudioSpec(nil)
arg selector = default
arg args = nil
ArgSpec:init 0x11a03c940
arg this = an ArgSpec(input, 0)
var specName = input
a FunctionDef 0x11a672640
sourceCode = ""
arg elem = input
arg i = 3
ArrayedCollection:do 0x11a77ee00
arg this = [ sine, freq, noise, input, mix, u_i_ar_0_bus, u_i_ar_1_bus, u_o_ar_0_bus ]
arg function = a Function
var i = 3
Collection:collectAs 0x11a672280
arg this = [ sine, freq, noise, input, mix, u_i_ar_0_bus, u_i_ar_1_bus, u_o_ar_0_bus ]
arg function = a Function
arg class = Array
var res = [ an ArgSpec(sine, 1), an ArgSpec(freq, 440), an ArgSpec(noise, 0) ]
Udef:init 0x11af211c0
arg this = a Udef(ringMod)
arg inFunc = a Function
var argNames = nil
var values = nil
Meta_Udef:new 0x11af1f140
arg this = Udef
arg name = ringMod
arg func = a Function
arg args = nil
arg category = nil
arg addToAll = true
a FunctionDef 0x125479bf8
sourceCode = "{ |sine = 1, freq = 440, noise = 0, input = 0, mix = 1.0|
var sig, modsig;
RandSeed.ir(1,12345); // for the noise
sig = UIn.ar(0,1);
modsig = (
SinOsc.ar(freq, 0, sine ) +
PinkNoise.ar( noise ) +
( UIn.ar(1,1) * input )
) * sig;

UOut.ar( 0, (sig * (1-mix)) + (modsig * mix) );

})
.category_( \effect )
.setSpec( \sine, \amp.asSpec )
.setSpec( \freq, FreqSpec(2,20000) )
.setSpec( \noise, \amp.asSpec )
.setSpec( \input, \amp.asSpec )
.setSpecMode( \sine, \normal, ...etc..."
a FunctionDef 0x11b53f300
sourceCode = ""
Function:prTry 0x119da29c0
arg this = a Function
var result = nil
var thread = a Thread
var next = nil
var wasInProtectedFunc = false

CALL STACK:
DoesNotUnderstandError:reportError 0x11f087068
arg this =
Nil:handleError 0x11f044e78
arg this = nil
arg error =
Thread:handleError 0x11ea5bd58
arg this =
arg error =
Object:throw 0x11f040d58
arg this =
Function:protect 0x118c65f98
arg this =
arg handler =
var result =
Interpreter:executeFile 0x12547a1e8
arg this =
arg pathName = "/Users/MacBook/Library/Appli..."
arg args = [_0]
var result = nil
var saveExecutingPath = "/Users/MacBook/Documents/Sup..."
< FunctionDef in Method Collection:collectAs > 0x11c9a2428
arg elem = "/Users/MacBook/Library/Appli..."
arg i = 52
ArrayedCollection:do 0x118561408
arg this = [_67]
arg function =
var i = 52
Collection:collectAs 0x1245d0838
arg this = [_67]
arg function =
arg class =
var res = [_52]
< FunctionDef in Method Collection:collectAs > 0x11ca5e128
arg elem = "/Users/MacBook/Library/Appli..."
arg i = 1
ArrayedCollection:do 0x118a923a8
arg this = [_2]
arg function =
var i = 1
Collection:collectAs 0x1245d1418
arg this = [_2]
arg function =
arg class =
var res = [*1]
Meta_GenericDef:loadAllFromDefaultDirectory 0x11c98f7e8
arg this =
Meta_ULib:getDefaultUdefs 0x11859f498
arg this =
Meta_ULib:getDefaultSynthDefs 0x11c95fe18
arg this =
var defs = nil
< FunctionDef in Method Meta_ULib:startup > 0x11ca23eb8
var defs = nil
...
^^ The preceding error dump is for ERROR: Message 'default' not understood.
RECEIVER: an AudioSpec(nil)

Start with UnitDefs/ringMod.scd and the ArgSpec:init, Udef:init, and Meta_ULib:startup frames shown in the report. Reproduce the failure through Ulib.startup and trace why AudioSpec(nil) receives default; done means startup completes without the reported DoesNotUnderstandError.