Carsten,

> org.firebirdsql.jdbc.FBSQLException: GDS Exception. 335544327. invalid
> request handle

Must be some bug in JayBird. For some reason driver sent a handle that was
already released.

> org.firebirdsql.jdbc.FBSQLException: GDS Exception. 335544344. I/O error

for file %.0s"write"

> null
> Error while trying to write to file
> null

No clue. Might be that there were no space left for the database or the temp
directory is full.

> java.lang.NullPointerException

A bug in a driver. For some reason JCA part tries to start a transaction on
a closed connection. Most likely caused by the code that re-opens a
connection if error happens between transactions.

I do not have any suggestion for you about how to fix them. I will have a
look into the NullPointerException, as this is most severe issue. Most
likely first error is related to this one.

Roman