Unable to umount filesystem whe shutting down

[Vittorio <vdemart@supereva.it>]

This is the first time it happens to me!

Under woody I've compiled my own, very light kernel 2.4.13-1 (Bunk's
stuff) for my hardware eliminating many options I don't need.

Now, it all works ok (in syslog there isn't anything strange or
missing dependency warning) but when I shutdown woody hangs endlessly
to "unmounting filesystems........" and I'm compelled to switch off
the PC. This causes a complete and annoying check of the partition
when booting again.

Why is that and what should I check?

Please help 

Vittorio