Can't open compressed file

[Eric <spam narcopia com>]

I've saved a dia file using the 'Compress diagram files' options but, once saved 
I can't reopen them.  I get the following error:

Error loading diagram /home/user/log_backup.dia.
Unknown file type.

If I save the file without the compression option I can open them fine.  Running 
file on the file I get the following file type:
$ file log_backup.dia
log_backup.dia: gzip compressed data, ASCII, extra field, encrypted

if I try to gunzip the file, I get
$ gunzip -S .dia log_backup.dia
gunzip: log_backup.dia is encrypted -- not supported

So apparently the file is encrypted but I don't see anything in the 
documentation about encryption.  Anyone have any ideas? I'm running Dia 0.95-1 
and I'm saving/opening using the same version.