[CentOS] An rpmbuild spec question

I'm trying to build a package to create a directory and install some
files. My rpmbuild keeps failing, unable to cd into the directory, "no
such". Now, in the tmpfile, I *see* it cd'ing into BUILD/opt, and the
source was unzipped and untared into BUILD/opt/smipmicfg-1.27.0. In the
spec file, I've even added a cd $RPM_BUILD_ROOT/opt, and I see it cd to
there... and then it says it fails cd'ing into the directory under it.

I've been doing a lot of googling, but nothing seems to fix this. Anyone
got a clue?

     mark