Technically speaking, there is no openacs process, just the aolserver (nsd). There were a couple of fixes lately in tcl/aolserver, so i would recommed to upgrade to aolserver 4.0.10 (avail since jan) and to tcl8.4.11.
what os are you using?
Under usual conditions you get some hints from the error-log file. Anything special about your setup?
what is the contents of /public/contents/my_domain_name/public/contents/
what is the size of you nsd-process, how many connection threads are defined (maxthread)?
