Cant open DFS namespace on any domain controller

Hi

I have a big problem. For some reason our dfs namespace is not accessible from the dfs control panel on any of our dc's inluding the PDC. we have server 2008 w/SP2 domain controllers and one server 2003 w/SP2 domain controller. The strange thing is that dfs is still operational and all files can be accessed as normal.

any ideas where i can start looking. i alsready used portqry to check if port 135 is listening on all dc's, which it is. I have restarted the dfs namespace as well as replication service and i have tried switching off the firewall completely. no luck on all accounts.

Thanks

Karl