Help! Unix server always reboots
 

When I start a server, some processes are started, then I get the following error message:

syncing discs... panic:
getnewbuf: locked buf
Uptime 1m20s
Automatic reboot in 15s

And it always reboots...

What is the problem and how can I break the rebooting cycle?

P.S.
All these happened when the server once freezed and I pushed reset... (What else to do then?)

start in runlevel 1 (single-user mode) and fsck

How to start it in runlevel 1? (It is FreeBSD.)
It starts up with the following menu after reboot:

F1 FreeBSD

I do not see any choice there. After some seconds it starts checking disks (and then reboots.)
I am a FreeBSD newbie, so I am consulting the FreeBSD handbook, but, since it is very urgent, I hope someone may be faster here...

Thanks for your attention!

Problem solved:
I could somehow stop the cycle and get into single user mode:
boot -s

Fsck did not find or corrected any errors in any file system; however, the server starts normally ever since. Strange...

Problem not solved; it happened again.

But now I think I found the reason: the server restarts with the locked buf error when a printer is connected to LPT1.
(Previously I was misleaded by the fact that file system errors were found after each restart.)
Now I will check if it is the port, the cable or the printer.