Access UI deletes only 1 row on linked tables

saerdna.relleom

I built an ms access 2007 application with an orracle 11g backend. The tables are linked via odbc, using an oracle 11g 32byte client. If I want to delete several records in a form or the linked tabele itself, I get an error and in the end there ist only one record deleted. If I want to delete the records, I highlight the concerning rows and either press the delete button or klick the delete button in the access menu. When I do this I get messages in the following sequence:

• The Microsoft Office Access database engine stopped the process because you and another user are attempting to change the same data at the same time. --> OK
• You are about to delete 1 record(s). If you click Yes, you won't be able to undo this Delete operation. Are you sure you want to delete these records? --> OK

Of course there is no other user (unless NSA.. but no!). To be sure it has nothing to do with oracle constraints or keys I created two test tables. One with a single column id PK and one with a composite PK of a number and a varchar2 column. There is no difference in behaviour between these two tables.