unionfs issues

Hi,

Recently (3 days ago) I upgraded my main server with 5.2.1, and then
cvsupped to latest current in order to solve some problems in 5.2.1.
Among those was the fact that unionfs was non-functional in the release.
  After cvsupping it seemed to work, but when doing some heavy file
copying operations inside a mountpoint the box paniced.

Problem is - the box is headless, 1000kms away, and with no serial
access. So I'll just ask if this is expected behaviour at the current
state of source, or if those in the know can say anything more about why
this happened and if it has already been fixed.

I apologise for the vague description of this problem - I know I'm
probably reaching for straws here.

Wbr.,
/Eirik