Cannot load Ruby extension (.so) checked into ClearCase

When I try to load a Ruby extension that I have checked into ClearCase,
something weird happens:

./lib/ 5: Access is denied. - ./lib/

If I check out the file, and make it ReadOnly, it still works, so it’s
not a
read-write-access-problem. Seems Ruby does some wierd stuff that the
ClearCase filesystem does not like. Filemon reports a lot of these:

14:13:30 ruby.exe:5804 UNLOCK <network_path_removed> RANGE
LOCKED Offset: 0 Length: -1

So Ruby requests to OPEN the file, the ClearCase file system for some
tries to do an UNLOCK instead of an OPEN. Any help appreciated.