Please help

[G7SUM]

Afternoon

I have a Ready NAS Duo V2 running Minim Server. It has worked beautifully for 7 years.
Yesterday, the back up drive in the ReadyNas died. The original drive still seems to be intact, however, I am now unable to access the shared folder.
I tried to upgrade to the latest Minimserver 2 but it gets to 77% and gives the message unrecognised server error occurred. I also have another error: minimserver start up error, Java 7 or later is required. I have tried to download several versions without success.
I am far from being an expert here and really need your guidance please.
I am accessing on Macbook pro 2017 model.

Many thanks in advance.

Gary