"The following has happened: Some months ago the DAQ (PCI6024E) card from the customer was broken and NI sended us an other card (other repaired card). We shipped it to the customer, but he is still trying to use this card"
Do you mean the card at one time was used error free ?
I assume, it has.
The first thing to do is to check on the card from measurement and automation (Max), and see if Max recognizes it. If not, then it is either that the driver got corrupted, or that the card is bad.
If you decide to reinstall Nidaq, the you have to first uninstall the existing Nidaq/Max, the reinstall Nidaq (same version that existed on the computer or the most recent one)