Mysql – Will re-installing phptheadmin will have any effect on the Databases

A socket file doesnt actually contain data, it transports it.. It is a special, unusual type of file created with special system calls/commands. It is not an ordinary file.

It is like a pipe the server and the clients can use to connect and exchange requests and data. Also, it is only used locally. Its significance is merely as an agreed rendezvous location in the filesystem.

Creating a plain old file and putting it in that location may actually interfere with the server creating it... and thereby prevent local clients from connecting to the server.

My recommendation is to remove any file you put in the location. The special socket file is created by the server.

The connection refused error is indeed the problem. Connection refused on unix sockets is not terribly intuitive, but it indicates that there is nothing listening on the socket (typically, the process is dead, or the file given as the address wasn't a socket at all). This should never be a permissions issue, unless dovecot is unable to open the socket for listening due to permissions.

Try stopping dovecot and postfix, removing the socket file at /var/run/dovecot/auth-userdb, and starting postfix and dovecot again (ensuring the user dovecot is running as has permissions on /var/run/dovecot). Usually this will fix this type of issue.

Netstat will also display unix domain sockets. Check its output (use netstat -nvlap | less and search for the path or for dovecot) to ensure dovecot is listening.