Caveat - I do not run an OpenACS site. But if OpenACS is a fairly straight port of ACS 3.2 the following should apply. You can turn off comments on static pages by adding your directory or other glob pattern to ad_naked_html_patterns (defined in tcl/ad_html.tcl), or you can use the AD_DND tag posted above in the pages themselves, or you can sync your html files in the data base (/admin/static/static-syncer-ns-set.tcl), then go to the "all pages in ___" listing (on /admin/static/index.tcl), click on an individual link (/admin/static/page-summary.tcl?page_id=1), and toggle the comment properties individually.
Probably the fastest option is edit the glob patterns. The most flexible - assuming you want comment on some of you pages and not others - would be to use the sync script to find your files and insert their location into the database - then update the table manually to set up the initial sets of files that do and do not accept comments. Then use the admin interface to continue maintianing and fine tuning commentability.
If you never want comments, ever, how about unregistering ad_serve_html_page?
