Sorry guys, i have to appologize a thousend times. When i create a new table in Access, i select the number field as foreign key ( I have done this many many times), but in this db i encountered a lot of linking problems. I made a test db and encountered the same error. My mind was jumping to conclusions.
What had happened: In the original db the number field had been changeg into a Double field instead of long integer ( i don't know how), but anyway, in the test db I made the mistake te select a memo field and got the same error, but this time because of a different reason. A reason i did't see. I was sure i selected a number field!
I was going around in circles. Sorry for wasting your precious time...