[Groff] trouble getting long names to work on Solaris

[Dorai Sitaram]

For a small file containing only the line

\f[CW]asdf\fP

groff 1.19 on Solaris, running in the default
non-compatibility mode, gives me 

             warning: can't find font '['

I've tried setting GROFF_TMAC_PATH, using the -M option
(neither of which I should have to do), all to no
avail.  I know groff 1.19 is indeed being called,
because the output .ps file mentions it.  The directory
in which I installed groff 1.19 has priority in my
PATH.

Any idea what could be going on?  This doesn't
happen on Linux groff 1.19.

--dorai