Kmail - subfolders and e-mails disappeared

Today I have noticed, all subdirectories and e-mails of a local folder sub-directory are disappeared.
But the respective files and folders are yet in /.kde/share/apps/kmail/mail/ !!
What can I do, in order to see the disappeared e-mails under kmail?
Please note: I haven’t made any change in Kmail configuration before this problem happened.

OS: openSUSE 10.2
Kde: 3.5.5
Kmail: 1.9.5

Thank a lot for any suggestion

Bye, redpine