Thanks. That works fine with a script executed from a commandline, or within an environment like Emacs. However, even there, no variation I have tried lets me use "slowops=0". The documentation for Devel::NYTProf says to use slowops if some of the functions have negative timings, but I can not tell from the documentation where such an assignment is supposed to be set. From the behaviour I see, that seems to be a way to use NYTProf within a CGI script as an alternative to setting the configuration parameters I'd used in httpd.conf.
Thus, the problem remains as to how to use slowops, and some of the other items I see in the documentation for NYTProf.