I had some troubles getting AOLserver/OpenACS to work on OpenBSD, as well. At first, certain errors from the database would cause segmentation faults; this was cured by using the postgres driver from OpenACS instead of the one from AOLserver. After that, I had lots of problems with zombie processes and "document contains no data" errors;
I removed the watchdog module, and I haven't had troubles since.
I'm really just a hobbyist as far as OpenACS and AOLserver are concerned, so I wasn't too interested in taking the time to figure out what exactly the problem is. I don't know tcl all that well, and so I imagine sifting through watchdog for the source of the problem would take a long time.
Just my $.02
