Forum OpenACS Q&A: Re: can i install 2 different versions of openacs in the same server?
NaviServer does not come with an nssha1 module, because it is not needed (the command "ns_sha1" is built-in, NaviServer supports, in addition, many more message digests such as sha2 and sha3 and others via ns_md, see ). The ns_sha1 module was removed from NaviServer more than 10 years ago... so i assume, your old version was based on AOLserver, and you are reusing an AOLserver configuration file.
In your case, you can remove the module loading the nssha1.so module from the configuration, but I would recommend using an actual NaviServer configuration file since you will like to use many of its features. The recommended configuration file is  is installed via install-oacs.sh.