This should work
***
r1 1 0 1
R2 2 0 1
X1 1 2 0 memristor
.SUBCKT memristor 1 2 6
Eres 1 9 POLY(2)
+(8, 0) (11, 0) 0 0 0 0 1
Vsense 9 4 DC 0V
Fcopy 0 8 Vsense 1
Rstep 8 0 1K
Rser 2 4 10
Fmem 6 0 POLY(2) Vsense
+VEcopy -0.5E-10 0 1E-10 0 -1 0 0 0 1
Cmem 6 0 90nF
Rsp 6 0 1000Meg
VEcopy 7 0 0 ;6 1
Rc 7 0 1
Ecpy2 10 0 6 0 1
Vref ref 0 DC 1V
R1 10 11 100K
Ssat1 11 0 0 11 SWX
Ssat2 11 ref 11 ref SWX
.MODEL SWX VSWITCH (Ron=0.001, Roff=1000Meg,
+Vt=0.00001V, Vh=0.00001V)
.ENDS
.op
.end
Changes - Switch Model in PSpice is VSWITCH, it is not SW.
Second problem is with F device "Fmem" - here you can use a E device as controlling source. The change above is convert E device to V - however you need to make sure model intent is not altered. Change above does not gurantee that