Routing problem

[eluser]wiredesignz[/eluser]
Phew that took some trial and error settings wise. (never having used $_GET)

Try setting $config['uri_protocol'] = "PATH_INFO"; and removing your regex route altogether.
Also set $config['enable_query_strings'] = TRUE;

This worked to the point that I was able to use the query ?oid=12345 and get to the controller and the $_GET variable is set.