We have FB 2.1.1 on Open Suse 11

There some errors in the firebird.log file that says:
"I/O Error for file '/opt/......fdb'
Error While trying to write to file
Invalid argument"

Nothing else.
There is a lot of them and after several ones, there is an
"...fbserver terminated abnormally (-1)" randomlly (almost 10 times a
day).
As an information that can help, there are some "read errno = 104"
entries in the log, also.

Any help to (at least) detect the source of the problem?

Thanks in advance.