You might try a DSN-less connection string :
provided you have a netbios share
$dsn = "Driver={Microsoft Access Driver (*.mdb)};Dbq=\myServer\myShare\myPath\myDb.mdb;Uid=admin;Pwd=;";
odbc_connect ( $dsn, "", "");
If your php parsing server is *NIX you might install or configure Samba.
I don't know if you can connect via ip address, I doubt it.
Again, do you have to use Access? I would just get WIN version of MySQL.