Can not write to tape /dev/nst0 any more using tar/star

[Gérard Milmeister]

There has been some time since I last use the DAT tape.
When I try to write some data using star I get the following
error:
star: Invalid argument. Error writing '/dev/nst0'

tar gives a similar error. /dev/st0 does not work either.
However mt seems to work as usual.
The kernel is 2.6.14-1.1656_FC4.
Some time ago everything worked perfectly.
-- 
Gérard Milmeister
Langackerstrasse 49
CH-8057 Zürich