bind makes RRSIG disappear?

[Gilles Massen]

Hello,

I have a very peculiar behavior: a zone, signed by OpenDNSSEC and pushed 
to Bind 9.7.2-P3 by scp was working fine. But now, completely out of the 
blue, Bind decides to claim some authority over the zone: the SOA RRSIG 
(only that one) is scrapped, and this is logged:

06-Feb-2011 15:10:59.373 general: warning: dns_dnssec_findzonekeys2: 
error reading private key file dns.lu/RSASHA256/16129: file not found
06-Feb-2011 15:10:59.373 general: warning: dns_dnssec_findzonekeys2: 
error reading private key file dns.lu/RSASHA256/13736: file not found

Additionally a journal file is build alongside the original zone file.

Why is this happening, and more importantly, how can I make it stop? 
Restarting bind/removing the journal had no effect whatsoever!

BTW, another instance of 9.7.2-P3 gets the same zone, the same way, and 
is still serving it normally.

Any help would be appreciated...

Best,
Gilles