ISC 2.0.2 possibly damaged file system

[bhutch at shine7.waterloo.edu]

My ISC 2.0.2 has been producing the following NOTICE since I
reinstalled it after repartitioning the hard disk:

  NOTICE: bad free block count in free list block on Primary
  AT Hard Disk unit 0, partition 4

  mount: possibly damaged file system

Partition 4 is /usr2, a 40M partition on a 200M IDE HD. The message
is produced on booting the system, when it mounts this partition.
Apparently, there is no other problem generated by the supposedly
damaged file system. I am not an expert on system administration
but tried to use the checkhdfsys sysadm script to check the partitions
on my HD and all I got was a message saying that there were no
partitions which could be checked by that script. The Famous Manual
(for version 2.2 -- ISC gave me version 2.0.2 because version 2.2
does not support IDE drives, but this is a long story) says nothing
about this message. 

How can I fix the bad free block count? Is it possible to fix it?
Do I have to reinstall the whole thing? 

Another question is what is `gendev', the device which uses interrupt
vector 5 on /etc/conf/cf.d/sdevice ? Can I disable it to avoid a 
conflict with my Microsoft Bus Mouse? The Famous Manual doesn't
have anything on `gendev' either...

Thanks in advance,

J.R. Setti - The Transport Group, Civil Engineering - U of Waterloo