I want to use a dbm-database. I can insert, but I can't replace or delete anything. 
E.g.:

<?php
$dbh = dbmopen( "./data/produkte", "c" )
 or die( "Couldn't open DBM-database!" );
// This is running!

dbminsert( $dbh, "Sonic Screwdriver", "23.20" )
 or die("Insert not possible!");
// This is running, too!

dbmreplace( $dbh, "Sonic Screwdriver", "25.20" )
 or die("Replace not possible!");
// Here I get the error-alert!

dbmdelete( $dbh, "Sonic Screwdriver" )
 or die("Delete not possible!");
// Here I get the error-alert, too!

dbmclose( $dbh );
?>

(No gdb-backtrace available, sorry)

Greetzz by da
Kruemelkiller