ERROR: dbConnect() unable to connect to database server "localhost"
Installation and Configuration
JR4 is only going to run on php up to php 5.2. Anything newer than that and it wont run properly. It MIGHT be an issue with the mysql version on the server. Just a guess, but if the mysql() set of functions are not on the server because its too new, that might be the cause of the issue.
At some point after JR4 phps 'mysql' set of functions got replaced with 'mysqli' set of functions. If your server does not have the older set of mysql functions that may be the issue.