The Records Center Configuration defaults to localhost as the SharePoint server. To change this, you must specify the the SharePoint server in the web.config file, which is located under C:\Program Files\Laserfiche\SharePoint Integration\LFSPRCConfigWebApp by default.
In the web.config file, your appSettings node is probably blank, like so:
<appSettings />
Add in the key SharePointServer like so (since you are on port 90):
<appSettings>
<add key="SharePointServer" value="localhost:90" />
</appSettings>
Sorry this was not in the documentation. I will see about getting that updated.