Problems with FDF in PHP

Hello,

the following problem occurs here:

When submitting FDF data from a PDF to a PHP script, the script gives
the following Errors:

fdf_close(): supplied argument is not a valid fdf resource

and

fdf_save() expects parameter 1 to be resource, boolean given

regardless if I open the FDF directly via fdf_open_string or save it
first and open it with fdf_open. The script worked before, the only
thing changed is the php.ini.

Environment: Suse 8.0, Apache 1.3.23, php 4.3.1, FDFTK 5.0

TIA
Arnim Sommer