(The somehow corrupted way of representing the data above seems to be the result of my copiing and pasting the files from a linux to a windows system).
The record wich I imported is (un-compiled with MarcEdit):
=LDR 00438nam 2200109 45e0 =008 \\960105s1970||||||||||||||||||||||||||||ger =245 04$aDie schönsten Helden- und Rittersagen des Mittelalters /$c[Für die Jugend bearb. von] Gerhard Aick ; Mit vielen Zeichnungen von Erich Hölle =260 \\$aWien :$bTosa Verlag,$c[ca. 1970] =300 \\$a508 S. :$bIll. ;$c23 cm =700 1\$aAick, Gerhard =700 1\$aHölle, Erich =942 \\$cBUCH$kSCHÖ =952 \\$p160$oSCHÖ$aSB$bSB$yBUCH
I you just have one corrupted record in you DB, just delete it! Find you corrupted record biblionumber. Delete matching records in 'biblio' and 'biblioitems' table. Do it with a MySQL front -end like PhpMyAdmin or directly with MySQL command line.