Hi,
Lately I've been seeing this often:

Starting...
insmod: cannot insert `/lib/modules/2.6.35/misc/logring.ko': Invalid module format (-1): Exec format error
modprobe: failed to load module logring
/etc/rc.d/run.d/S02logring: 10: cannot create /dev/log241: No such device or address
/etc/rc.d/run.d/S02panic: 2: cannot create /dev/log241: No such device or address
Jan 1 00:00:11 localhost syslog.info syslogd started: BusyBox v1.00 (2010.09.21-13:23+0000)
/etc/rc.d/run.d/S05syslog: 4: cannot create /dev/log240: No such device or address
/etc/rc.d/run.d/S06mipsdog: 2: cannot create /dev/log241: No such device or address
/etc/rc.d/run.d/S07rb: 3: cannot create /dev/log241: No such device or address
/etc/rc.d/run.d/S08softdog: 3: cannot create /dev/log241: No such device or address
Starting services...
/etc/rc.d/run.d/S10nova: 29: cannot create /dev/log1: No such device or address

Fatal error 0x853
Please contact support@mikrotik.com

connect failed (errno=2)


Shutting down...
Stopping services...
connect failed (errno=2)
Jan 1 00:00:12 localhost syslog.info System log daemon exiting.
/etc/rc.d/run.d/C95panic: 2: cannot create /dev/log241: No such device or address
System halted.

Any ideas what's causing this?

what RouterOS version is that and what does
/system check-installation

report when you run it?

I'm running the 5.0rc2 on RB411
I don't have one in front of me since I format and reinstall.
How can I '/check installation' at this stage?

please upgrade to newer RouterOS version, there are no reason to use release candidate version when there are 12 updates to final. Also that rc is one of the first that where released.