Floating node in LTspice

I have a question about designing power amplifier.

Question: Find the current of the current source I3.

My solution: I supposed that the Vbe of Q1 is 0.6v and with Is=10^(-14) calculated the Ic1, then I supposed that the Vbe of Q3 and Q4 is 0.67 V and found the Ic3 and Ic4, similarly, I calculated the remaining parameters using the information mentioned in the simulation, so I found I3=0.32 mA.

***Problem: I have floating node error in simulation for the source node of M2.

This is my simulation:

My guess: I think that the NMOS command has a bug.

This is code of my simulation:

Version 4 SHEET 1 880 712 WIRE -720 -48 -976 -48 WIRE -352 -48 -720 -48 WIRE 48 -48 -352 -48 WIRE 320 -48 48 -48 WIRE 48 0 48 -48 WIRE 320 0 320 -48 WIRE 256 48 192 48 WIRE -720 96 -720 32 WIRE -528 96 -720 96 WIRE -400 96 -528 96 WIRE -160 96 -304 96 WIRE -976 112 -976 -48 WIRE -720 112 -720 96 WIRE 48 176 48 80 WIRE 192 176 192 48 WIRE 192 176 48 176 WIRE -848 192 -928 192 WIRE -768 192 -848 192 WIRE 48 192 48 176 WIRE 320 208 320 96 WIRE 448 208 320 208 WIRE 496 208 448 208 WIRE -848 240 -848 192 WIRE -528 240 -528 96 WIRE -496 240 -528 240 WIRE -352 240 -352 160 WIRE -352 240 -416 240 WIRE -288 240 -352 240 WIRE -160 240 -160 96 WIRE -160 240 -208 240 WIRE -64 240 -160 240 WIRE -16 240 -64 240 WIRE 320 304 320 208 WIRE -976 320 -976 208 WIRE -720 336 -720 208 WIRE -64 336 -64 240 WIRE 192 352 192 176 WIRE 256 352 192 352 WIRE -976 400 -976 320 WIRE -720 400 -720 336 WIRE -64 464 -64 416 WIRE 48 464 48 288 WIRE 48 464 -64 464 WIRE -848 480 -928 480 WIRE -768 480 -848 480 WIRE -976 496 -1104 496 WIRE -528 496 -720 496 WIRE -432 496 -528 496 WIRE 448 496 448 208 WIRE 448 496 -352 496 WIRE -528 512 -528 496 WIRE -848 528 -848 480 WIRE -848 624 -848 608 WIRE -656 624 -848 624 WIRE 48 624 48 464 WIRE 48 624 -656 624 WIRE 320 624 320 400 WIRE 320 624 48 624 FLAG -1632 592 0 FLAG -1744 592 0 FLAG -1904 592 0 FLAG -1504 592 0 FLAG -528 592 0 FLAG 496 288 0 FLAG -352 -48 Vcc FLAG -1632 512 Vcc FLAG -848 240 Vb FLAG -1904 512 Vb FLAG -1184 496 Vin FLAG -1504 512 Vin FLAG 448 208 Vout FLAG 48 176 Ve2 FLAG -64 240 Vb2 FLAG -352 240 Vb1 FLAG -720 96 Vd1 FLAG -976 320 Vd3 FLAG -720 336 Vd4 FLAG -656 624 Vee FLAG 48 624 Vee FLAG 320 624 Vee FLAG -1744 512 Vee FLAG -848 480 Vs3 SYMBOL npn 256 0 R0 SYMATTR InstName Q3 SYMATTR Value mynpn SYMBOL npn -400 160 R270 SYMATTR InstName Q1 SYMATTR Value mynpn SYMBOL pnp 256 400 M180 WINDOW 3 87 65 Left 2 SYMATTR Value mypnp SYMATTR InstName Q4 SYMBOL pnp -16 288 M180 SYMATTR InstName Q2 SYMATTR Value mypnp SYMBOL current -720 -48 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName I2 SYMATTR Value 1m SYMBOL res 480 192 R0 SYMATTR InstName R_load SYMATTR Value 100 SYMBOL res -192 224 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R5 SYMATTR Value 10k SYMBOL res -400 224 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 100k SYMBOL nmos -768 112 R0 SYMATTR InstName M1 SYMATTR Value mynmos SYMBOL nmos -768 400 R0 SYMATTR InstName M4 SYMATTR Value mynmos SYMBOL nmos -928 400 M0 SYMATTR InstName M3 SYMATTR Value mynmos SYMBOL nmos -928 112 M0 SYMATTR InstName M2 SYMATTR Value mynmos SYMBOL current 48 0 R0 WINDOW 3 37 56 Left 2 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR Value 0.2m SYMATTR InstName I4 SYMBOL current -64 336 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName I3 SYMATTR Value 0.32m SYMBOL res -544 496 R0 SYMATTR InstName R3 SYMATTR Value 10k SYMBOL res -336 480 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 10k SYMBOL res -1088 480 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 5k SYMBOL voltage -1904 496 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 5 SYMBOL voltage -1744 608 R180 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V2 SYMATTR Value 10 SYMBOL voltage -1632 496 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V3 SYMATTR Value 10 SYMBOL voltage -1504 496 R0 WINDOW 123 24 124 Left 2 WINDOW 39 24 152 Left 2 SYMATTR Value2 AC 0 0 SYMATTR SpiceLine Rser=0 Cpar=0 SYMATTR InstName V4 SYMATTR Value 0 SYMBOL current -848 528 R0 WINDOW 3 36 39 Left 2 WINDOW 123 0 0 Left 0 WINDOW 39 24 28 Left 2 SYMATTR Value 2m SYMATTR SpiceLine load SYMATTR InstName I1 TEXT -1952 -208 Left 2 !.model mynmos NMOS(Kp=250u Vto=0.6 lambda=0.1 W=1000u L=10u phi=0 gamma=0) TEXT -1952 -272 Left 2 !.model mynpn AKO: 2N3904 (bf=200) TEXT -1952 -240 Left 2 !.model mypnp AKO: 2N3906 (bf=150) TEXT -1968 -336 Left 2 ;commands TEXT -1960 -88 Left 2 !.op TEXT -1960 -48 Left 2 !;ac lin 100 1k 100k RECTANGLE Normal -976 -176 -1968 -304