analoglib mtline

dear all,
It is the first time I post here.
I used mtline for t-line in spectre.
I obtain s-parameter from hfss and then convert to RLGC
and used with mtline for one line case, it is good.
But when I tried to do the same thing for a diffrential line,
I convert the 4-port s-paramter from hfss into mixed-mode
s-parameter, and then convert them to mixed-mode RLGC,
then I entered the following in the mtline RLGC entries:
Rdd Rdc Rcd Rcc
Ldd Ldc Lcd Lcc
Gdd Gdc Gcd Gcc
Cdd Cdc Ccd Ccc

("d" stands for differential-mode, "c" stands for common-mode)

after starting SP simulation, there is this message:

warning during spectre hierachy flattening
warning (CMI-2114) defineQ:unit of quantity "Q" is changed from "coul" to "C"
warning (CMI-2114) defineFreq:unit of quantity "F" is changed from "N" to "Hz"

And it shows the SP satrts runing.

Then the simulator just hangs there.

Could anybody tell me what the problem may be and how I can solve it? I need differential line in spectre for S-parameter and transient simulation.

Thank you very much.