Could nt access my asa5510? - Cisco ASA 5510 Firewall

If you are trying to access it remotely (via telnet or SSH), you will need to enable management on the interface that you are access it on, and it is also advisable to tie an access list to it.

If you are trying to access it via http, you will need to switch on http management with something like: http 0.0.0.0 0.0.0.0 inside

hope that helps!