Vco design problem in awr

hello
while simulation VCO in (Microwave office/Analog Environment) by AWR using 0.18 um Tech. i am finding following problems
Pl help me to fix these problems

1) Measurement - VCO_SSDEL:OSC_FREQ()[*] : Measurement requires an oscillator simulator
2) Measurement - VCO_SSDEL:Vtime(DCVS.V4,1)[*] : Unable to compute Vtime measurement
3) Measurement - VCO_SSDEL:DB(L_USB_F(PORT_1,0,1))[*] : Measurement requires an oscillator simulator
4) Step size for source stepping has decreased below a minimum allowed value
5) Failed to find start-up conditions in the specified frequency range.

thanks in advance
Rk