NML Backup Problem with *.ft Directories

Hello,

sometimes we have a problem to backup Notes Data. It fails with this message:

XXX:NOTES:Error opening the directory D:\Lotus\Domino\Data\mail\arose.ft\ftgi\Fulldel\Supp.DEL\.

or

XXX:NOTES:Error opening the directory D:\Lotus\Domino\Data\mail\arose.ft\ftgi\Itemdel\Supp.DEL\.

Our Notes Admins says that *.ft directories are for temp index informationen.
We use NML 3.0 with Option to backup all Files in Data directory.

I`ve created an directive but it seems not to work.
<< ftgi >>
+skip: *

Have anybody an idea how to solve this?

Regards,
Andreas