Hi, thanks for clarifying that for me! I see I was a bit confused, and confirmed our table names do not have a prefix. My ISP does however force our ISP username as the first X characters of the user & database names - that's what threw me off. So, I have set the prefix back to "" and then hardcoded the user & database names with the first X characters.
I'm still getting a 500 error, and having trouble tracking that down. I've been reading the "white screen" thread and our .htaccess looks good with "RewriteBase /gallery".
I'm still able to access the old host, and over there I get this message:
Zenphoto has detected a change in your installation.
Zenphoto 1.4.9[36167d6556] has been copied over an unknown release.
The change detected is critical. You must run setup for your site to function.
However, I don't think anything got copied over, though something might have become corrupted over the years(?). I wonder what triggers that message. Would failure to access the DB be a reason?
Any idea where / what system log file to look at?
Further troubleshooting thoughts appreciated!